JP7686784B2 - Refrigerated warehouse management system, defrosting judgment processing device, and refrigerated warehouse management method - Google Patents

Description

The present invention relates to a refrigerated warehouse management system, a defrosting determination processing device, and a refrigerated warehouse management method.

In the refrigeration units used in refrigerated warehouses, frost gradually grows on the surface of the heat exchanger of the cooler during the process of cooling the air inside the warehouse. When frost grows on the surface of the heat exchanger, heat transfer between the refrigerant flowing inside the cooler and the surrounding air is impeded, which can lead to a decrease in cooling performance. For this reason, defrosting operations are generally performed as necessary to melt the frost on the heat exchanger surface.

Methods for melting frost during defrosting operation include raising the temperature of the refrigerant flowing inside and using a heater or water spray as an external heat source. However, when melting frost, the heat exchanger and surrounding air are also heated, which is an unnecessary heat source for a refrigerated warehouse. Therefore, from the viewpoint of energy conservation, it is desirable to perform defrosting operation as few times as possible. Here, since it is difficult to accurately detect the amount of frost on the heat exchanger surface, it is common to start defrosting operation after a specified period of cooling operation assuming that frost has formed. However, since the amount of frost varies depending on the humidity of the surrounding air, the amount of frost is not necessarily constant even if the cooling operation time is the same.

When the amount of frost becomes excessive, not only does the efficiency of cooling operation decrease, reducing energy efficiency, but it can also cause reliability issues, such as making it easier for residual frost to form after defrosting operation. For this reason, it is generally necessary to limit the cooling operation time, and the increased number of defrosting operations is one of the factors that reduces energy efficiency.

To address this issue, for example, Patent Document 1 discloses a technology for an air conditioner that compares the drive current of an outdoor fan with a preset reference current to determine whether or not frost has formed on the outdoor heat exchanger, and claims that it is possible to accurately determine whether or not frost has formed on the outdoor heat exchanger. This conventional technology further discloses that the drive current supplied to the outdoor fan a predetermined time after the start of heating operation or the end of defrosting operation may be stored as a reference current.

Furthermore, Patent Document 2 discloses a vehicle air conditioning system that includes a current value detection means for detecting the current value of the blower driven during heating operation, a current value determination means for determining whether the difference between the current value of the blower before frost formation and the detected current value exceeds a predetermined value, and a control means for switching from heating operation to defrosting operation when it is determined that the predetermined value has been exceeded. An example is disclosed in which the current value of the outdoor fan at the start of heating operation when no frost has formed on the outdoor heat exchanger is used as the current value before frost formation.

Japanese Patent Application Publication No. 11-287538 Japanese Patent Application Publication No. 10-338025

As described above, in order to appropriately switch between cooling and defrosting operations, a current reference value, which is the fan current value under specified conditions, such as the current value before defrosting operation, may be used. Here, the inventors have found that various factors such as the surrounding environment in the warehouse and residual frost on the cooler affect the reliability of the current reference value. This viewpoint is neither disclosed nor suggested in either Patent Document 1 or Patent Document 2, and is not recognized as an issue.

For example, the air flow in the warehouse may change due to changes in environmental conditions such as frost on the walls and the amount and arrangement of stored logistics products, and the current reference value may fluctuate. In addition, when the amount of frost is more than expected, the frost may not be completely melted by the defrosting operation and may remain as residual frost. If the fan current value in the state where there is residual frost is set as the reference value without considering such surrounding environmental conditions and the presence of residual frost, the amount of frost may be erroneously estimated, and the amount of frost may be greater than expected. An unexpected increase in the amount of frost is undesirable because it leads to a decrease in cooling performance. Therefore, it is desired to provide a management system for a refrigerated warehouse equipped with a reliable frost amount estimation technology that can prevent an excessive increase in the amount of frost by considering various factors such as changes in the surrounding environment in the warehouse and residual frost on the cooler.
The above-mentioned Patent Documents 1 and 2 do not take into consideration that various factors such as the ambient environment in the warehouse and residual frost on the cooler affect the reliability of the current reference value.

According to a first aspect of the present invention, the following cold storage management system is provided. That is, the cold storage management system controls a cooling device capable of switching between cooling operation and defrosting operation. The cold storage management system includes a current measurement unit, a memory unit, and a control unit. The current measurement unit measures the current value of a blower that blows air for the cooling device. The memory unit stores a reference current value that is the current value of the blower and serves as a reference for estimating the amount of frost during cooling operation. The control unit calculates the difference between the current value measured by the current measurement unit and the reference current value, and performs control to switch from cooling operation to defrosting operation when the calculated difference value reaches a predetermined value. The control unit updates the reference current value stored in the memory unit based on the current value measured by the current measurement unit during cooling operation and the reference current value.

According to a second aspect of the present invention, the following defrosting determination processing device is provided. That is, the defrosting determination processing device controls a cooling device that can switch between cooling operation and defrosting operation and adjusts the temperature in a freezer. The memory unit stores a reference current value that is a current value of a blower that blows air for the cooling device and serves as a reference for estimating the amount of frost during cooling operation. The processor calculates a difference between the current value of the blower and the reference current value, and performs control to switch from cooling operation to defrosting operation when the calculated difference value reaches a predetermined value. The processor updates the reference current value stored in the memory unit based on the current value of the blower during cooling operation and the reference current value.

According to a third aspect of the present invention, the following freezer warehouse management method is provided. That is, the freezer warehouse management method is a method for adjusting the temperature in a freezer warehouse by controlling a cooling device that can switch between cooling operation and defrosting operation. The freezer warehouse management method includes a step of acquiring a current value of a blower that blows air for the cooling device, a step of calculating a difference between the acquired current value and a reference current value that is a current value of the blower and serves as a reference for estimating the amount of frost during cooling operation, and a step of switching from cooling operation to defrosting operation when the calculated difference value reaches a predetermined value, and a step of updating the reference current value based on the current value acquired during cooling operation and the reference current value.

According to the present invention, the amount of frost can be accurately estimated even when there are changes in the frost condition on the surrounding structures or the amount of stored goods, making it possible to build an energy-saving and highly reliable refrigerated warehouse management system. In addition, a defrosting determination processing device and a refrigerated warehouse management method having similar effects are provided.

FIG. 1 is a diagram illustrating an example of a system configuration according to a first embodiment. FIG. 2 is a side view illustrating an example of a freezer interior in which a cooler is disposed in the first embodiment. FIG. 13 is a diagram for explaining an operation according to the conventional technique. 4 is an example of a control flowchart of the refrigeration device according to the first embodiment. FIG. 4 is a diagram illustrating an example of the operation of the refrigeration device according to the first embodiment. FIG. 4 is a diagram illustrating an example of the operation of the refrigeration device according to the first embodiment. 13 is an example of a control flowchart of a refrigeration device according to a second embodiment. FIG. 11 is a diagram illustrating an example of the operation of the refrigeration device according to the second embodiment. FIG. 11 is a diagram illustrating an example of the operation of the refrigeration device according to the second embodiment. 13 is an example of a control flowchart of a refrigeration device according to a third embodiment. FIG. 11 is a diagram illustrating an example of the operation of the refrigeration device according to the third embodiment. FIG. 13 is a diagram showing an example of a time series change in a reference value base. 2 is a diagram illustrating an example of the configuration of a defrosting determination processing unit. FIG. 4 is an example of a control flowchart of a refrigeration device. FIG. 1 illustrates an example of a system configuration.

First Embodiment
A first embodiment of the present invention will be described with reference to FIGS.

Figure 1 is a diagram showing an example of a system configuration in an embodiment of the present invention. In this embodiment, a freezer warehouse for storing items includes four freezer compartments (50a, 50b, 50c, 50d), and a refrigeration device 1 is used to cool each freezer compartment. The following explanation will be given representatively as refrigeration device 1, but the freezer warehouse can also be a refrigeration device, and the freezer warehouse can also be a refrigerator. In addition, in a freezer warehouse or refrigerated warehouse, items such as, but not limited to, food, alcoholic beverages, medicines, vaccines, etc. are stored or kept while maintaining a predetermined temperature.

The refrigeration device 1 comprises a heat source unit 9 equipped with a compressor etc., and a refrigeration cycle consisting of coolers (10a to 10d shown) provided in freezing chambers 50a to 50d connected by refrigerant piping 8, and each cooler (10a to 10d) operates based on instructions from an operation control processing unit 15 so that the temperature inside each freezing chamber (50a to 50d) becomes a predetermined temperature.

Each cooling unit (10a to 10d) is equipped with a current sensor (20a to 20d shown) that detects the current value flowing through the built-in fan, and the refrigeration device 1 uses the measurement value of this current sensor to determine whether or not defrost operation is necessary in the defrost determination processing unit 21, and if it is determined that defrost operation is necessary, a signal is sent to the operation control processing unit 15 to perform the defrost operation.

Here, the operation control processing unit 15 and the defrost determination processing unit 21, which are equipped with a processor and perform the actual control and determine whether or not switching between defrosting operation and cooling operation is necessary, are sometimes collectively referred to as the control unit. Note that in this example, the operation control processing unit 15 and the defrost determination processing unit 21 are described separately, but they may be included in the same configuration. In other words, they may be one configuration having the functions of these configurations.

The refrigeration device 1 also has a memory unit (not shown). The memory unit stores a reference current value indicating the current value when the fan is operated under a specified condition, which is used by the defrost judgment processing unit 21 when determining whether or not a defrost operation is required. Here, the specified condition may be, for example, a state immediately after the end of a defrost operation in an environment inside a freezer warehouse at a certain point in time, where there is no residual frost. The reference current value is the current value flowing through the fan that is being driven. The memory unit may be provided in the defrost judgment processing unit 21, as an example. The memory unit is appropriately configured using a memory or the like.

In the refrigeration device 1, the fan 12 rotates at a constant speed, which makes it easier for the current sensor 20 to detect the current value. Therefore, when an inverter is provided, it is preferable to detect the current value at a constant speed. On the other hand, a correction formula for the rotation speed and current value of the fan 12 may be prepared in advance, and the detected current value may be appropriately corrected using the correction formula. As an example, this correction formula may be stored in the memory unit.

As shown in Fig. 1, the refrigeration device 1 may be configured to be able to communicate with a work management server 201 and a power management server 202 via a network. First, the refrigeration device 1 will be described in detail as an example of a cold storage warehouse management system. Then, an example of a cold storage warehouse management system further configured using the work management server 201 and the power management server 202 will be described.

2 is a side view of an example of a freezer room 50 in which a cooler 10 is arranged. In the freezer room 50, various distribution items 40 brought in by an operator through an entrance 51 are stored on shelves 52 installed inside. In this example, the cooler 10 is placed on a mounting plate 55 arranged above the entrance 51, and the cooler 10 is equipped with a fan 12, which is an example of a blower that blows air in the freezer room 50 to a cooling heat exchanger 13 cooled by a refrigerant. The cooler 10 uses the fan 12 to flow the air in the freezer room 50 to the cooling heat exchanger 13 cooled by a refrigerant, thereby maintaining the temperature of the air in the freezer room 50 and the distribution items 40 stored therein within a predetermined temperature range.

Here, the air in the freezer 50 is always kept at a negative temperature (for example, the air in the freezer 50 is managed to be kept at -20°C). For this reason, moisture in the air that flows from the outside to the inside of the freezer 50 when goods 40 are brought in or taken out easily turns into frost, and adheres to and grows on various locations, including not only the surface of the cooling heat exchanger 13, but also the surface 30e of the cooler 10, the surface 30c of the ceiling and the surface 30d of the wall in the freezer 50, the surface 30b of the mounting plate 55, and the surface 30a of the shelf 52. In FIG. 2, an example of frost 30 that has adhered and grown is shown in grayscale (30a to 30e).

When frost accumulates and grows in this way, the differential pressure required for the fan 12 to circulate the air inside the freezer compartment 50 increases. This changes the amount of air that the fan 12 can blow and the torque and current required to rotate the motor 11 that drives the fan 12. Note that this embodiment assumes that a propeller fan is used as the fan 12, and in the case of a propeller fan, the value of the current flowing through the fan 12 generally increases as the required differential pressure increases.

The refrigeration device 1 uses this characteristic to estimate the amount of frost and control the defrosting operation using the current value detected by the current sensor 20, specifically estimating the amount of frost according to the amount of change in the current value. Note that when a fan with different characteristics is used (for example, when a multi-blade fan is used), the fan current may decrease as the required differential pressure increases, but the present invention is applicable in either case. Furthermore, the number of freezer compartments 50 and coolers 10 is not limited to the number shown in the embodiment.

Before describing the detailed processing in this embodiment, the problems in the conventional technology will be described again with reference to FIG. 3. FIG. 3 relates to the conventional technology, and the horizontal axis of the graph is time. FIG. 3 shows the movement of three times from the (n-2)th to the nth times, in the case where the operation from the end of defrosting to the start of cooling operation until the next defrosting operation is counted as one operation. Here, the three graphs on the top and bottom show, from top to bottom, the actual amount of frost on the surface of the cooling heat exchanger, the fan current, and the estimated amount of frost over time. In the example of FIG. 3, the movement is shown when the fan current at the start of the cooling operation is set as the reference value, and in the (n-2)th operation, the fan current value ia at the start of the cooling operation is set as the reference value base.

As the cooling operation continues, the amount of frost on the surface of the cooling heat exchanger increases, so the load on the fan for blowing air increases and the fan current also increases. At this time, the difference value x of the fan current value with respect to the reference value base is correlated with the amount of increase in the load on the fan, i.e., the amount of frost, so the estimated amount of frost is calculated using the difference value x. Therefore, when the difference value x reaches a predetermined threshold value d, it is determined that the estimated amount of frost has reached a predetermined limit amount of frost mf, and a defrosting operation is started based on this determination. By using the difference value x in this way, it is possible to estimate the amount of frost and control the timing of starting the defrosting operation according to the amount of frost.

Now, consider the case where residual frost occurs in such conventional technology. In the example of Figure 3, it is assumed that the frost has been removed by the defrosting operation (i.e., there is no residual frost) at the start of the (n-1)th cooling operation, and the fan current ib at the start of the cooling operation drops to the reference value base, so operation is performed based on this reference value base. In this case, the amount of frost (actual amount of frost) and the estimated amount of frost match.

However, if residual frost occurs during the defrosting operation after the (n-1)th operation, the ventilation resistance of the cooling heat exchanger remains large even when the defrosting operation is completed, so the fan current ic at the start of the cooling operation is large relative to ia. Here, in the conventional technology, the operation is started with the fan current ic at the start of the cooling operation as the reference value base, so even if there is actually frost, it is determined that there is no frost and operation is started. Therefore, when the difference value x reaches the threshold value d, the estimated amount of frost is mf, but the actual amount of frost increases to mf2, which is greater than mf. In this way, in the conventional technology, there was a possibility that the actual amount of frost would be greater than expected. Furthermore, in this case, since the amount of frost is considered to be large, not only is there a possibility that residual frost will occur again even if the defrosting operation is performed, but there is also a high possibility that the absolute amount of residual frost will also increase with subsequent operations. In other words, once such a state is reached, the residual frost will gradually increase, which may lead to a decrease in the heat transfer performance of the cooling heat exchanger and a rise in the temperature inside the freezer due to insufficient cooling performance.

As described above, in the conventional technology, it is possible to estimate the amount of frost during cooling operation even if there is residual frost, but it may not be possible to appropriately suppress the actual amount of frost to mf. Furthermore, it is thought that it is not easy to appropriately manage the frost not only in the cooling heat exchanger but also in the surrounding area.

The processing of this embodiment to address such problems will be explained with reference to an example control flowchart shown in Figure 4 and operation examples shown in Figures 5 and 6.

In this embodiment, the control unit (more specifically, the defrost determination processing unit 21) acquires the fan current i from the current sensor 20 at the time when the cooling operation is started (S401, S402). The control unit then compares it with the reference value Prebase, which is the previous reference current value (S403), and if the fan current i is equal to or less than the previous reference value Prebase, updates the reference value base with the value of the fan current i (S404). On the other hand, if not, the control unit leaves the reference value base at the previous reference value Prebase (S405).

An example of the operation of S403 to S405 will be described with reference to Figure 5. In the example of Figure 5, the fan current ib at the start of the (n-1)th cooling operation is compared with the previous reference value base(n-2), and since the two values are equal, the new reference value base(n-1) is updated with the fan current ib (S403, S404).

On the other hand, in the nth time when residual frost occurs, the value of the fan current ic at the start of the cooling operation is greater than the previous reference value base(n-1), so the previous reference value base(n-1) is used as the new reference value base(n) for the nth time (S403, S405), rather than the fan current ic. Therefore, the difference value x at the start of the cooling operation is not 0, and the difference value x is a value corresponding to the amount of residual frost. Therefore, even if residual frost occurs, the amount of frost can be correctly estimated, and a difference between the estimated amount of frost and the actual amount of frost can be prevented.

Furthermore, in this embodiment, as shown in Fig. 4, during cooling operation, the control unit periodically acquires the fan current i (S406) and compares it with a reference value base (S407). If the acquired fan current i is equal to or less than the reference value, the control unit updates the reference value to the value of the fan current i (S408), and if not, does not change the reference value (S409).

An example of the operation of S406 to S409 will be described with reference to Figure 6. In the example of Figure 6, in the (n-1)th operation, when the fan current ib at the start of cooling operation is compared with the previous reference value base(n-2), the fan current ib is smaller, so the reference value base(n-1) is updated to the fan current ib (S407, S408).

In this way, if the fan current ib falls below the previous reference value due to some factor, the control unit updates the reference value to the fan current ib and lowers it. In other words, if the reference value is not lowered, the difference value x starts from a negative value rather than 0, and when it reaches the predetermined limit value d (threshold value d) of the difference value, the actual amount of frost may be greater than the estimated amount of frost. Therefore, in this embodiment, the reference value (for example, the reference value base (n-1) in FIG. 6) is updated to a low value and the difference value x from the updated reference value is calculated, so that such an unexpected increase in the amount of frost can be avoided and the estimation error of the amount of frost due to a change in the surrounding environment can be reduced. Note that various factors can be considered as factors for such a decrease in the reference value, such as when some frost on the surface of the cooling heat exchanger 13 remains until the end of the previous defrosting operation, when the amount of frost attached to the surrounding walls, etc. decreases, and when the amount of logistics goods 40 stored in the freezer 50 decreases.

Furthermore, the decrease in the fan current value due to such factors does not necessarily occur only at the start of cooling operation. Therefore, in this embodiment, the reference value base can be periodically corrected not only at the start of cooling operation but also during cooling operation (loop LB in Figure 4). Next, an example of this operation will be described with reference to Figure 6.

As shown in FIG. 6, in the nth operation, the fan current ic at the start of the cooling operation is equal to the previous reference value base(n-1), so as described above, the reference value base(n) is set equal to the fan current ic, i.e., base(n-1). However, if the value of the fan current i becomes equal to or less than the reference value base(n) during the continuation of the subsequent cooling operation, the reference value base is periodically corrected in the loop LB as described above, and the reference value is periodically updated (S407, S408). Therefore, not only for the first time when the cooling operation starts, but also during the cooling operation, if the fan current i is equal to or less than the reference value base(n), the reference value base(n) is periodically updated, and the difference value x from the updated reference value is calculated.

This allows the amount of frost to be estimated while taking into account changes in the environment in the freezer 50, making it possible to build a more reliable frost monitoring system. For example, not only when residual frost occurs in the cooling heat exchanger 13, but also when the load applied to the motor 11 for the fan 10 fluctuates due to changes in the surrounding environmental conditions, etc., the reference value base of the fan current i can be periodically updated so that the estimated amount of frost increases, so that it is possible to avoid the actual amount of frost becoming excessive due to an underestimation of the amount of frost, and a highly reliable system can be built. In addition, even if an estimation error remains, the estimated amount of frost increases by lowering the reference value according to the present invention, so that a system with increased reliability can be built compared to the case where the amount of frost is underestimated.

This process is performed, and a determination is periodically made as to whether the difference value x has reached the threshold value d (S410). Then, when the difference value x has reached the threshold value d, the process related to the loop LB is terminated and the next process is executed.

4, in this control flow, the final base value base during the operation at the time when the difference value x becomes equal to or greater than the threshold value d is stored as the previous base value Prebase (i.e., the previous base value for the next operation) (S411). Then, after the defrosting operation is started and completed (S412, S413), the system returns to the cooling operation by loop LA, and the cooling operation is performed.

Therefore, the fan current value i at the start of cooling operation and during cooling operation is compared with the previous reference value Prebase or reference value base, and the reference value base is updated to the fan current i only when the fan current value i is equal to or less than the previous reference value Prebase or reference value base. In other words, based on a comparison of the fan current value i during cooling operation with the reference value, it is determined whether or not the reference value needs to be updated, and if there is a possibility that the amount of frost may be overestimated, it is determined that the reference value needs to be updated. This makes it possible to avoid erroneously estimating the reference value base and excessively underestimating the amount of frost, and to build a more reliable system.

Therefore, according to this embodiment, a cold storage management system is provided that controls a cooling device that can switch between cooling operation and defrosting operation, and includes a current measurement unit that measures the current value of a blower that blows air for the cooling device, a memory unit that stores a reference current value that is the current value of the blower and serves as a reference for estimating the amount of frost, and a control unit that calculates a difference between the current value measured by the current measurement unit and the reference current value, and controls the system to switch from cooling operation to defrosting operation when the calculated difference value reaches a predetermined value. The control unit determines whether or not the reference current value stored in the memory unit needs to be updated based on a comparison between the current value measured by the current measurement unit during cooling operation and the reference current value, and when it is determined that the reference current value needs to be updated, updates the reference current value based on the current value measured by the current measurement unit.

The storage unit stores load information relating to the relationship between the current value of the fan 12 and the operating load, and the control unit may update the reference value base to the one with the smaller operating load of the fan 12 between the fan current value i and the previous reference value Prebase based on the load information at the start of the cooling operation. In this way, it is possible to update the reference current value taking into account the operating load of the fan 12. The load information may be information indicating the relationship between the current value and the operating load of a blower other than the fan 12. The load information may be information indicating, for example, that there is a positive correlation between the current value and the operating load of the blower. In this case, if the current value of the blower increases, it indicates that the operating load has increased, so it can be estimated that the amount of frost has increased. As an example, in the case of a propeller fan, the current value flowing through the fan 12 generally increases with an increase in the required differential pressure, so it is considered that there is a positive correlation between the current value of the fan and the operating load. There may also be a negative correlation between the current value of the blower and the operating load depending on the characteristics of the blower. In this case, if the current value of the blower decreases, it indicates that the operating load has increased, and therefore it can be estimated that the amount of frost has increased. In this case, if the current value of the blower is smaller than the previous reference value at the start of the cooling operation, the previous reference value may be adopted as the new reference value. Also, if the current value of the blower is equal to or greater than the reference value during the cooling operation, the reference value may be periodically corrected and periodically updated.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to Figures 7 to 9. Note that descriptions that overlap with or are similar to those described above may be omitted.

Figure 7 shows an example of a control flowchart in the second embodiment of the present invention. In this embodiment, the reference value base can be both increased and decreased, whereas in the first embodiment shown in Figure 4, the reference value base is not increased in the control flow. While the reference value base can be changed both upward and downward, a limit is set on the range of change of the reference value base. Furthermore, the reference value base can only change downward in the loop LB during cooling operation.

Therefore, in this embodiment, the reference value base may increase only once during one control flow of loop LA at the start of cooling operation. That is, the first process, which is a process for increasing the reference value base, may be performed only once at the start of cooling operation. On the other hand, the reference value base may decrease once at the start of cooling operation, and the number of times the process is performed in loop LB. That is, the second process, which is a process for decreasing the reference value base, may be performed once at the start of cooling operation, and the number of times the process is performed in loop LB. Therefore, the frequency of the decrease in the reference value base is higher than the frequency of the increase in the reference value base. In this way, in this embodiment, while the change in the reference value base is permitted in both the upward and downward directions, the change width is limited, and the frequency of passing through the flow that causes the change in the upward and downward directions is changed, and the number of times the flow of the change in the downward direction is increased, thereby improving the followability to residual frost and changes in the environment.

7, in this embodiment, the control unit (specifically, the defrost determination processing unit 21) acquires the fan current i from the current sensor 20 at the start of the cooling operation (S701, S702) and compares it with the reference value Prebase, which is the reference current value at the start of the previous cooling operation (S703). Then, when the fan current i is equal to or greater than the previous value Prebase, the control unit updates the reference value base by adding the smaller of the maximum value (Ux1) of the change range by which the set reference value is increased and the difference between the value of the fan current i at the start of the cooling operation and the previous reference value Prebase as the change amount to the previous reference value Prebase (S704). On the other hand, when the fan current i is smaller than the previous reference value Prebase, the control unit updates the reference value base by subtracting the smaller of the maximum value (Dx1) of the change amount by which the set reference value is lowered or the difference between the previous reference value Prebase and the value of the fan current i at the start of cooling operation as the amount of change from the previous reference value Prebase (S705).

In this embodiment, the control unit periodically acquires the fan current i during cooling operation (S706) and compares it with the reference value base (S707). If the acquired fan current i is equal to or greater than the reference value, the control unit calculates the difference value x without updating the reference value base (S708). On the other hand, if the acquired fan current i is smaller than the reference value, the control unit updates the reference value base by lowering it using the smaller of the maximum change amount (Dx2) by which the set reference value is lowered and the difference between the reference value base and the value of the fan current i as the change amount, and calculates the difference value x from the updated reference value base (S709).

An example of the operation of S703 to S710 will be described with reference to Figures 8 and 9. First, an example of the operation related to S704 (the operation of increasing the reference value base when the cooling operation starts) will be described with reference to Figure 8.

Figure 8 shows data from eight operations from the (n-4)th to (n+3)th operation, and assumes that the load on the fan 12 has increased due to some factor at the start of the nth operation. Examples of factors that may cause the load on the fan 12 to increase include a sudden increase in the amount of distribution goods 40 in the freezer 50, or a sudden increase in the amount of frost 30 in the freezer 50 due to high humidity conditions at the time of the distribution goods 40 being brought in. If such factors make it difficult for the wind to flow in the surrounding environment, the fan current i will increase even if there is no frost on the surface of the cooling heat exchanger 13, so it is desirable to use the increased fan current i as the reference value base. However, when the current value at the start of the cooling operation is high, it is not easy to distinguish between a change in environmental conditions and a case due to residual frost.

Therefore, in this embodiment, a limit is set on the amount of change in the reference value base so that appropriate measures can be taken. Specifically, as described above, the maximum amount of change is predetermined as Ux1. Then, the smaller of the value of Ux1 and the difference between the fan current value i at the start of the cooling operation and the previous reference value Prebase is added to the reference value Prebase as the amount of change. Therefore, in the example shown in FIG. 8, when the fan current value ia at the start of the nth cooling operation becomes high, the difference between the fan current value ia and the previous reference value Prebase is compared with the maximum amount of change Ux1 that has been determined in advance, and if the difference is greater than Ux1, the reference value base is raised from the previous reference value Prebase by Ux1 (S704).

In this case, the estimated amount of frost will not be estimated lower than the actual amount of frost. In addition, by repeating this operation (by gradually increasing the reference value base each time defrosting is performed), the reference value base gradually approaches the appropriate value, so that even if a small amount of frost may occur transiently, there is no concern that the amount of frost will become excessive. Therefore, the reference value base can be corrected to an appropriate reference value so that the amount of frost does not become excessive.

In addition, in this embodiment, a case where the amount of frost on the ceiling and wall surfaces increases suddenly is shown as an example, but if these changes are slow and the frost grows over a long period of time, the difference between the estimated amount of frost and the actual amount of frost is small. In this way, even if the difference between the estimated amount of frost and the actual amount of frost is small, the reference value base can be adjusted to follow the influence of the growth of the frost by appropriately setting the value of the change amount Ux1.

Note that there may be a risk in raising the reference value if residual frost occurs, but this risk can be minimized by keeping the range of change in the reference value small each time. Generally, it takes time for frost to grow, so if the range of change Ux1 is set to the same level as the detection accuracy of the fan current (for example, 0.1 A), this risk can be almost eliminated.

Next, referring to Figure 9, an example of an operation related to S705 (operation of lowering the reference value base when cooling operation starts) and an example of an operation related to S709 (operation of lowering the reference value base during cooling operation) will be described.

When frost grows on the walls, etc., it may impede the flow of air to the cooling heat exchanger 13, so as an example, frost removal may be performed as part of maintenance work. In such cases, unlike frost growth, the frost is removed in a short period of time, making it easier for the air to circulate inside the freezer, reducing the load on the fan and resulting in a large drop in the fan current i.

In this embodiment, for such a case, a limit is set so that the value does not fall below a predetermined maximum amount of change Dx1 immediately after the start of cooling operation, and the reference value base is updated up to Dx1 (S705). If this change is insufficient, the control unit gradually updates the reference value base while comparing it with the predetermined maximum amount of change Dx2 each time it periodically acquires the fan current value i thereafter (S709).

Figure 9 shows an example of operation when the fan current value ia at the start of the nth operation is significantly lower than the previous reference value base(n-1). In this case, the difference between the fan current value ia and the previous reference value base(n-1) is greater than the maximum change amount Dx1, so the cooling operation starts with a reference value base(n) that is Dx1 lower than the previous reference value base(n-1). Then, after dt hours, that is, when the fan current is acquired again, the deviation from base(n) is still large, so the reference value base(n) drops by the maximum change amount Dx2. By repeating this operation every dt hours (periodically), the reference value base(n) reaches its lower limit (i.e., the same value as the fan current).

Here, the time required for cooling operation before starting defrosting operation is, for example, about 10 hours per operation, while the control period dt is very short at about 1 minute. Therefore, even if it is necessary to repeat the operation several times until the reference value base(n) falls to a predetermined value, the frost will not grow during that time, and even if this operation is repeated several times, there will be almost no error in the estimation of the amount of frost. In addition, the setting of Dx2 prevents a sudden drop in the reference value base due to the influence of noise.

According to this embodiment, it is possible to correct the reference value of the fan current not only when residual frost occurs, but also when frost grows in the surrounding environment, or conversely, when the frost disappears from the surrounding environment, thereby enabling flexible response to changes in the environment within the freezer compartment 50.

As explained above, when the difference value x reaches the threshold value d, the process exits from loop LB (S710), the reference value Prebase is stored as the previous reference value (S711), defrosting operation is started (S712), and the defrosting operation is ended (S713).

Third Embodiment
Next, a third embodiment of the present invention will be described with reference to Figures 10 to 13. Note that descriptions that overlap with or are similar to those described above may be omitted.

Figure 10 shows an example of a control flow chart in the third embodiment of the present invention. This embodiment is substantially similar to the second embodiment in control flow before frost, i.e. while the maximum difference xmax is 0 (i.e., in Figure 10, S1008 to S1010). On the other hand, the main difference is that when the maximum difference xmax is greater than 0 in loop LB, i.e., after frost, a control flow (S1011 to S1015) is added.

The maximum difference xmax here is the maximum value of the difference x from the start of a defrosting operation until the next defrosting operation, i.e., during one pass through loop LA. It is then periodically updated to a larger value compared to the difference x at the end of loop LB (S1016), and when the difference x exceeds the threshold value d and exits from loop LB (S1017), the maximum difference xmax is reset to 0 (S1018).

The added control flow (S1011 to S1015) will be described with reference to Figure 10. After frost has formed, i.e. when the maximum difference xmax is greater than 0 (S1007), a control flow is executed to compare the calculated difference value x with the maximum difference xmax. Normally, when the amount of frost gradually increases, the difference value x gradually increases, but this control flow is for dealing with the opposite case where the difference value x decreases.

In this control flow, the control unit calculates the difference value x as the difference between the fan current i and the reference value base (S1011), and if the difference value x becomes smaller than the previous maximum difference value xmax (S1012), calculates the difference Delta between them (S1013). Then, if the difference Delta is equal to or greater than a predetermined threshold value Xx (S1014), the control unit lowers the reference value base by the difference Delta and simultaneously recalculates the difference value x using the new reference value base (S1015). Thus, by the processes of S1011 to S1015, the difference value x is updated to the same value as the maximum difference value xmax.

Next, referring to Figure 11, an example of operation related to S1011 to S1015 (updating the difference value after frost formation) will be described.

In Figure 11, the (n-2)th and (n-1)th operations are the same as those shown in Figure 4 etc. In the nth cooling operation, the fan current ic at the start of the cooling operation is equal to the previous reference value base(n-1), so the control unit starts the cooling operation with the fan current ic0 as the new reference value base(n) and periodically calculates the estimated amount of frost from the difference value x.

In this operation example, it is assumed that at a certain point F, the fan current suddenly drops by h from ic1 to ic2. Various factors can be considered as causing such a drop, such as an extreme decrease in the amount of stored goods, or when frost around the cooler is removed in a relatively short period of time due to maintenance, etc. When such an event occurs, the fan current drops significantly even though the amount of frost on the cooling heat exchanger 13 has not decreased.

If the reference value base is not corrected, the estimated amount of frost will drop sharply as shown by the dashed line in Figure 11 because the estimated amount of frost is based on the difference value x, resulting in a large discrepancy between the estimated amount of frost and the actual amount of frost. Therefore, in this embodiment, a process is added to lower the reference value base (n) by the amount of this change.

Specifically, the control unit compares the difference value x = ic2 - ic0 (first difference value) with the maximum difference value xmax = ic1 - ic0 (second difference value) up to that point (S1012). Then, when the difference value x is smaller than the maximum difference value xmax, the control unit obtains the difference between the maximum difference value xmax and the difference value x (S1013). Then, when the obtained difference is equal to or greater than a predetermined threshold value Xx (S1014), the control unit performs a process of lowering the reference value base (n) by the change in the difference value h (S1015). Note that here, an example of lowering the reference value base (n) by the change in the difference value h (i.e., the difference between the first difference value and the second difference value) has been described, but as an example, a process of lowering the reference value base (n) by a value smaller than the change in the difference value h may be performed.

By adding this process, even if the fan current drops significantly due to the surrounding environment, the amount of frost can be accurately estimated by lowering the reference value base by the amount of that change.

Thus, according to this embodiment, not only when residual frost occurs, but also when the current value fluctuates greatly due to changes in the surrounding environment, the amount of frost can be correctly estimated by following the change, so that it is possible to start the defrosting operation at an appropriate timing according to the amount of frost. Therefore, in a control that starts the defrosting operation when the cooling operation time reaches a predetermined time, there is a problem that the defrosting operation is often performed when the actual amount of frost is small. However, in this embodiment, since the start of the defrosting operation can be determined at an appropriate timing according to the amount of frost, it is possible to avoid performing the defrosting operation when the amount of frost is small. Therefore, it is possible to reduce the number of defrosting operations that were a thermal load in the freezer room 50, and control with improved energy efficiency is possible. Therefore, by applying this embodiment, a highly reliable and energy-efficient monitoring system for a freezer warehouse can be constructed.

In this embodiment, the processes of S1001 to S1005 and S1019 to S1020 are similar to those described above, so their description will be omitted.

As mentioned above, frost on the walls and floors around the cooler 10 makes it difficult for air to flow, so in cold storage warehouses, managers regularly monitor the interior of the warehouse to check for excessive frost buildup and, if necessary, remove the frost. The need for this maintenance work is, for example, left to the discretion of the manager.

As described in the embodiment, it is possible to change the reference value base for estimating the amount of frost to follow changes in the surrounding environment. Therefore, by storing the reference value base for a long period of time, it becomes possible to see (understand) changes over time. Therefore, it is possible to use the stored reference value base as an index representing the amount of frost in the surrounding environment.

Figure 12 shows an example of time series changes in the reference value base. The reference value base obtained in this example will gradually increase over time as frost grows in the surrounding environment. Then, by performing the above-mentioned maintenance at point F1, the reference value base will decrease, and then as the frost grows again, the reference value base will gradually increase. This type of movement will be repeated. Therefore, by setting an upper limit bmax for the reference value base, and by setting in advance, as an example, that maintenance will be performed when the reference value base exceeds the upper limit bmax, it becomes possible to determine whether or not maintenance is necessary from the data, rather than from the administrator's subjective judgment.

Maintenance to remove frost is carried out in the low-temperature environment of a refrigerated warehouse, and is a task that places a heavy burden on workers. However, the necessity of this work can be quantitatively determined based on data, and this data can be used to plan and carry out efficient work, thereby reducing fluctuations in the amount of frost that occurs during work. In addition, the number of workers required and the amount of work time can be estimated with greater accuracy, making management easier. Another benefit is that the work of monitoring the frost status can be simplified. Note that as the amount of frost in the surrounding environment increases, fan current increases, so from the perspective of energy conservation, it is better to have less frost, but frequent maintenance work increases labor costs, so it is thought that an appropriate balance must be struck.

The increase in power consumption is proportional to the area of the dashed line in FIG. 12, so bmax can be set so that maintenance can be performed at an appropriate time by comparing it with the operating costs, for example. Also, by visualizing the fluctuations in the reference value base as shown in FIG. 12, it becomes easier to predict when maintenance will be required, which has the advantage of making management easier. From this perspective, the control unit may output data related to the reference value base to an appropriate display device. For example, as shown in FIG. 12, data related to the change in the reference value base over time may be output.

Here, the display format is not particularly limited; for example, a graph may be displayed as shown in Figure 12, or the reference value base for each specified time period may be displayed in table format.

The control unit may also determine whether bmax is being approached by performing a threshold judgment, and cause a warning device (e.g., a lamp or buzzer) to output a warning to that effect when bmax is approached. The control unit may also cause a warning device to output a warning when bmax is reached. In other words, the control unit may issue an alert when the reference current value exceeds a predetermined threshold. The warning by the warning device may be issued in conjunction with the display by the display device, or may be issued in place of the display by the display device.

In this way, it is possible to construct a highly reliable and energy-efficient cold storage management system that can accurately estimate the amount of frost and appropriately control the timing to start defrosting operation, as well as a cold storage management system that can simultaneously estimate the frost condition in the environment surrounding the cooler and determine whether maintenance is necessary.This not only reduces the burden on the manager, but also allows for the construction of a cold storage management system that can provide the manager with information that is useful for determining the appropriate maintenance frequency, including work costs, and for formulating work plans.

The present invention is not limited to the above description and includes various modifications. For example, it is possible to add, delete, or replace part of the configuration of the embodiment with other configurations.

As shown in FIG. 13, the defrosting judgment processing unit 21 (defrosting judgment processing device) can be configured as a device including a processor 101, a memory unit 102, an input unit 103, an output unit 104, and a display device 105, as an example. Here, the input unit 103 is configured as an input interface to which a measurement value detected by a current sensor is input, and the output unit 104 is configured as an output interface to output a control signal to the outside for operating the cooler 10 appropriately. The processor 101 executes the above-described process based on the measurement value by the current sensor and the reference current value stored in the memory unit 102, and outputs a control signal for operating the cooler 10 in an appropriate operation from the output unit 104. In addition, the processor 101 can display the above-described data (for example, data related to the reference value base) on the display device 105. In this example, the defrosting judgment processing unit 21 is provided with the display device 105, but the display device 105 may be provided outside the defrosting judgment processing unit 21.

The refrigeration device 1 (refrigerated warehouse management system) only needs to be able to execute a predetermined operation, and a processor having a processing function may be incorporated in the defrost determination processing unit 21 as in the example of FIG. 13, or may be disposed outside the defrost determination processing unit 21. Similarly, the memory unit may be incorporated in the defrost determination processing unit 21, or may be disposed outside the defrost determination processing unit 21.

The processor may be capable of executing a predetermined process, and may be configured, for example, using a CPU (Central Processing Unit), a microprocessor, etc. The storage unit may be capable of appropriately storing data used in the predetermined process (for example, the previous reference value prebase, a program used to execute the predetermined process, etc.), and may be configured, for example, using a HDD (Hard Disk Drive), ROM (Read Only Memory), etc. Also, a RAM (Random Access Memory) may be used as appropriate.

An example has been described in which a cooler 10 is used as the cooling means (cooling device), but as long as the contents of the freezer can be appropriately frozen and stored, any suitable device such as an industrial freezer may be used as the cooling means (cooling device).

If no display is required, the display device may be omitted.

The process of the flowchart described above is merely an example, and the control flow can be modified as appropriate. For example, a control flow as shown in FIG. 14 may be executed. This control flow (S1401 to S1418) is similar to the control flow shown in FIG. 10 described in the third embodiment, but differs mainly in that in loop LB, in addition to the process of updating the difference value x, a process of comparing the fan current value i with the reference value base is periodically executed regardless of whether frost is present.

Furthermore, by using a reliable cold storage warehouse management system that can correctly estimate the amount of frost as described above, it becomes possible to grasp the frost state and estimate the time for defrosting operation more accurately. Based on such information, it becomes possible to properly manage the power of the cold storage warehouse, which contributes to cost reduction by reducing the amount of power used in the cold storage warehouse. It can also contribute to improved energy efficiency. Furthermore, applying the present invention to cold storage warehouse management can contribute to reducing the generation of greenhouse gases throughout the cold storage warehouse.

Next, a system including the refrigeration device 1 described above, the work management server 201, and the power management server 202 will be described. This system is an example of a cold storage management system, and can be used for solutions such as power management at a certain base. The work management server 201 includes a work planning system that creates and manages work information including work details and work schedules such as loading and unloading in the cold storage (50a to 50d). The power management server 202 includes a power management system that monitors the power consumption status in the cold storage (50a to 50d), manages the available power consumption, and creates power information including information on power costs and power usage schedules (power schedules) in a specified time period. The work planning system may be implemented separately from the cold storage management system. In this case, the work planning system can be implemented as long as the work information planned by the work planning system and information on the amount of temperature rise inside the cold storage caused by opening and closing the door of the cold storage due to the loading and unloading of goods are provided to the cold storage management system. The available power consumption may be information that manages power consumption in a specific time period so that it does not exceed a specified upper limit.

As described above, from the viewpoint that a defrosting operation is performed when the estimated amount of frost reaches a predetermined value, the control unit of the refrigeration device 1 specifies a first defrosting operation schedule in which a defrosting operation is performed. Here, as an example, the control unit specifies the time until the estimated amount of frost reaches the predetermined value based on the current estimated amount of frost. After the specified time has elapsed, the control unit can set a first defrosting operation schedule in which the cooler 10 performs a defrosting operation.

Here, if the time for performing the defrosting operation, which is the first defrosting operation schedule, overlaps with the time when the amount of work such as loading and unloading of goods stored in the freezer warehouse is greater than a predetermined amount, the temperature inside the freezer warehouse may rise due to the loading and unloading of goods while the inside of the warehouse cannot be cooled during the defrosting operation. In this case, if the first defrosting operation schedule cannot be changed, it is advisable to set the temperature of the freezer warehouse lower than the initial set temperature before performing the defrosting operation. This makes it possible to maintain the temperature of the freezer warehouse even if outside air enters due to the loading and unloading of goods without changing the first defrosting operation schedule. In addition, if multiple cooling units 10 are provided, it is also possible for the cooling units 10 that do not perform the defrosting operation to perform the above processing.

The control unit of the refrigeration device 1 may specify a second defrosting schedule so that the defrosting operation does not overlap with the time of work inside the warehouse, based on the work information including the work schedule acquired from the work management server 201 and the work time when the door of the freezer warehouse is opened and closed depending on the amount of goods to be carried in and out of the freezer warehouse. This reduces the load caused by the work inside the warehouse and the temperature rise inside the freezer warehouse caused by the heat from the defrosting operation entering at the same time, and contributes to improving the storage quality and energy saving of the freezer warehouse. In addition, the work information includes not only the time when the door of the freezer warehouse is opened and closed, but also the number of times the door is opened and closed, and the load on the cooler increases when the temperature inside the warehouse rises due to the carrying in and out of the goods. Therefore, it is preferable to control the defrosting operation so that it ends before the time when the goods are carried in and out as much as possible. It is preferable to perform the defrosting operation of the cooler 10 when no goods are carried in or out, but it is preferable to perform it during a time period when the carrying in and out of goods is less than a predetermined time or a predetermined number of times. In addition, it is preferable to perform the defrosting operation not only when the carrying in and out of goods is a predetermined time or a predetermined number of times, but also during a time period when the outside air temperature is lower than a predetermined temperature. By combining and comprehensively evaluating the outside air temperature and the time or number of times goods are brought in and out, and selecting a time period during which the temperature in the freezer warehouse is unlikely to rise, it is possible to carry out the defrosting operation more efficiently.

In terms of power consumption, it is considered that the power consumption in the defrosting operation is greater than that in the cooling operation that maintains the temperature in the freezer warehouse constant. This is the case when the defrosting operation is performed by blowing warm air to the cooling fan that has frost. For example, in a warehouse equipped with multiple coolers 10, while the temperature state is stable or changes little, the cooling operation is performed with the number of coolers that can guarantee the cooling capacity required to maintain a stable or small change state among the multiple coolers, and the other coolers may perform defrosting operation or be on standby. In such a case, the power consumption during the time period when the other coolers perform defrosting operation is greater than the time period when the other coolers are on standby. Therefore, if the time period when the luggage is loaded and unloaded, which requires a lot of power consumption for cooling, overlaps with the time period when the other coolers perform defrosting operation, the peak power consumption during a specific time period may increase.

Therefore, the control unit may obtain information on the power consumption during peak power consumption in the area where the cold storage warehouse is installed from the power management server 202 that manages the power consumption in the area, and control the control unit to specify a schedule in which defrosting operation is not performed during the time period related to the peak power consumption. That is, when the control unit determines that a defrosting operation is necessary, the control unit further determines whether the time period in which the first defrosting operation schedule for performing the defrosting operation overlaps with the peak power consumption, and sets and controls the second defrosting operation schedule so that the defrosting operation is performed during a time period different from the peak power consumption. This contributes to not increasing the base load of electricity because the defrosting operation, which consumes more power than the cooling operation, is not performed during the peak power consumption. In other words, it is possible to contribute to reducing greenhouse gas emissions by reducing the amount of use of thermal power generation, etc., as a balancing force for the base load. In the above example, it has been described that the overlap between the time period of peak power consumption and the time period of the defrosting operation schedule is determined, but the administrator, etc., can set a time period in advance in which defrosting operation is not performed, not limited to peak power consumption.

In addition, when the control unit calculates the increase in the amount of frost and determines that a defrosting operation is required, if there is a time period before or after the initial time period when the defrosting operation is to be performed in which the number of times or the duration of opening and closing of the door of the freezer warehouse is less than in the initial time period, the defrosting operation can be performed during that time period. This reduces the temperature change inside the freezer warehouse, and the power consumption of the entire freezer warehouse can be reduced. In other words, when a first defrosting operation schedule is specified, if a time period with less temperature change inside the freezer warehouse can be specified before and after the first defrosting operation schedule based on the work information and the outside air temperature information, the time period before and after that time period is specified as the second defrosting operation schedule.

In addition, if there is a time period before or after the initial time period when the outside temperature of the freezer warehouse is lower than the initial time period when defrosting operation is to be performed, it is advisable to perform the defrosting operation during that lower time period. In this way, by performing the defrosting operation during a time period when the temperature rise inside the freezer warehouse is low, normal cooling operation can be performed during the time period when the temperature rise inside the freezer warehouse is high, making it less likely that the temperature in the freezer warehouse will change. The time period when the defrosting operation is performed can also be changed taking into consideration both the time periods when the number of times or duration of door opening and closing is low and the time periods when the temperature rise inside the warehouse is low, and by performing the defrosting operation during a time period that satisfies both, the energy saving effect can be further increased.

Furthermore, the control unit may take into account information on the power cost contained in the power information, and if there is a time period when the power consumption cost is low, control the defrosting operation to be performed during that time period. As an example, a first defrosting operation schedule for performing the defrosting operation is determined whether the power consumption cost in the specified first time period exceeds a predetermined threshold, and if it exceeds the predetermined threshold, a second defrosting operation schedule is set and controlled so that the defrosting operation is performed during a second time period when the power consumption cost is lower than the first time period. During the time period when power is low, surplus power can also be used for power generation, which may reduce the environmental load.

In this way, the cold storage warehouse management system can use information from the power management server 202 to identify a defrosting operation schedule that takes power consumption into consideration. Furthermore, from the perspective of reducing power consumption, it is possible to reduce maximum power consumption due to peak shifting. As a result, it is possible to reduce the impact of the cold storage warehouse as a whole on the power generation peak of the power plant, and to reduce the amount of greenhouse gases generated overall.

In this explanation, an example has been described in which the cold storage warehouse management system specifies a defrosting operation schedule for multiple warehouses at one location, but this system can also be operated for multiple locations. In this case, the work management server 201 and the power management server 202 may be configured to be able to communicate with the refrigeration equipment 1 at each location. The work management server 201 and the power management server 202 may be able to communicate with the work planning system and power management system that manage the locations, and may communicate with each other to obtain information about each location.

A display device may be disposed at a base, and information used for selecting whether to select defrosting operation in advance to a time period when the number of loading and unloading operations of goods is greater than a predetermined value, or to select defrosting operation after loading and unloading operations, may be output to the display device, and a schedule for defrosting operation may be specified according to a selection input by an administrator of the management system of the cold storage warehouse as a representative user. The user's input may be performed using an appropriate input device. Information on the timing of defrosting operation may be output to the display device, and a schedule for defrosting operation based on the timing or time period permitted by the user may be specified using an appropriate input device. Meanwhile, the control unit may automatically perform defrosting operation according to the specified schedule.

Next, an example of a cold storage warehouse management system will be described with reference to FIG. 15. As explained above, this system can be used for solutions such as power management at a certain location. Note that explanations similar to those already explained may be omitted.

As shown in Figure 15, this system includes an integrated management system 301 that is configured to be able to communicate with each base via a network, and omits the work management server 201 and power management server 202 described above. The integrated management system 301 performs integrated management of each base based on data from each base.

First, the configuration of the base side, i.e., the freezer side, of this system will be described. In this example, the freezer operates one or more refrigeration devices 1 and includes a work management unit 311 and a power management unit 312. The work management unit 311 stores base-specific work management data 317, which is data related to work management for each base. The base-specific work management data 317 is, for example, information on work such as loading and unloading luggage at the base and storage information on items to be worked on. The power management unit 312 stores base-specific power management data 318, which is data related to power management for each base. The base-specific power management data 318 is, for example, information on the amount of power consumed at the base and the power usage status of the refrigeration device 1. The work management unit 311 and the power management unit 312 can be configured using an appropriate storage device, but may also be configured by a server that manages the bases, for example.

Next, the integrated management system 301 will be described in detail. The integrated management system 301 comprises a processing unit 302 and a memory unit 303. The processing unit 302 can be configured using an appropriate processing device, and performs data processing using data from each base. The memory unit 303 is configured using an appropriate storage device, and stores work management data 307, which is data related to work management, and power management data 308, which is data related to power management. Here, the work management data 307 is data that is an appropriate compilation of base-specific work management data 317 from each base. The power management data 308 is data that is an appropriate compilation of base-specific power management data 318 from each base.

The integrated management system 301 manages the amount of power consumption at each site and develops a power usage plan and a work plan based on the acquired power management data 308 and work management data 307. In addition, as described above, the integrated management system 301 specifies a defrosting operation schedule based on the power usage plan.

As an example of use in a power management solution for multiple bases, the integrated management system 301 may specify a defrosting operation schedule to reduce overall power consumption based on the power management data 308. Here, as described above, the integrated management system 301 can specify a time period during which defrosting operation is not performed so that the time period during which there is a lot of loading and unloading of luggage does not overlap with the time period during which defrosting operation is performed. In addition, a schedule for not performing defrosting operation during a time period related to peak power consumption at multiple bases may be specified. In particular, when specifying a schedule for not performing defrosting operation during a time period related to peak power consumption at multiple bases, a schedule may be specified in which control is performed so that defrosting operation is not performed at one or more bases and defrosting operation is performed at other bases within a range in which the total power consumption does not exceed the peak power. In this case, multiple candidates may be specified for a combination of defrosting operation schedules, that is, at which base (or cooler) defrosting operation is performed during a predetermined period at multiple bases. Then, a display screen (display unit) for the administrator may display the schedule candidates for which base defrosting operation is performed in a selectable manner. In this case, to support the manager's selection, the work plan, power usage plan, power cost, and the amount and type of goods handled at each base may be output on the display screen. For example, for each schedule candidate, information on the power consumption efficiency or power cost information at each base may be calculated and displayed together with the schedule candidate. This provides more appropriate support for the manager's selection. On the other hand, the integrated management system 301 may automatically determine the base at which the defrosting operation should be performed based on predetermined criteria.

Furthermore, the integrated management system 301 may identify a schedule for performing defrosting operation during a time period when power consumption costs are low, if such a time period exists.

In addition, the integrated management system 301 may determine which locations should be prioritized for cooling based on the amount and type of goods handled at each location, and may specify a schedule in which defrosting operations are given priority at locations where cooling is not required.

The data proposed and the data identified by the integrated management system 301 may be displayed on an appropriate display device located at the base. Also, in a manner similar to that described above, a schedule for defrosting operation may be specified in response to an input by an administrator of the cold storage management system.

1. Refrigeration equipment (refrigerated warehouse management system)
10 Cooler (cooling device)
12 Fan (blower)
15 Operation control processing unit 20 Current sensor (current measurement unit)
21 Defrosting determination processing unit (defrosting determination processing device)
201 Work management server 202 Power management server 301 Integrated management system

Claims (21)

A refrigerated warehouse management system that controls a cooling device that can switch between a cooling operation and a defrosting operation,
a current measuring unit that measures a current value of a blower that blows air into the cooling device;
A memory unit that stores a reference current value that is a current value of the blower and serves as a reference for estimating the amount of frost during a cooling operation;
A control unit that calculates a difference value between the current value measured by the current measuring unit and the reference current value, and performs control to switch from a cooling operation to a defrosting operation when the calculated difference value reaches a predetermined value,
The control unit is
updating the reference current value stored in the memory unit based on the current value measured by the current measuring unit during a cooling operation and the reference current value;
The control unit is
comparing a first difference value, which is a difference value between the current value of the fan at a predetermined timing and the reference current value, with a second difference value, which is a maximum value of the difference value between the current value of the fan and the reference current value from a cooling operation start point to the predetermined timing;
When the first difference value is smaller than the second difference value by a predetermined threshold value or more, the reference current value is updated to be lower than the previous reference current value.
A cold storage warehouse management system characterized by the above . The cold storage management system according to claim 1 ,
The control unit is
updating the reference current value by decreasing the reference current value by the difference between the magnitude of the first difference value and the magnitude of the second difference value;
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 1 ,
The control unit is
When the reference current value exceeds a predetermined threshold value, control is performed to notify an administrator by an alarm device that the amount of frost has exceeded a specified amount.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 1 ,
The storage unit is
The updated reference current value is stored.
The control unit is
and controlling a display device to display a time series change in the reference current value.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 1 ,
The control unit is
determining a schedule for performing a defrosting operation of the cooling device based on the estimation result of the current frost state;
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 5 ,
The control unit is
Acquire operation information for one or more cold storage facilities;
and determining a schedule for performing a defrosting operation of the cooling device based on the work information.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 5 ,
The control unit is
Acquire power information for one or more cold storage warehouses;
and determining a schedule for performing a defrosting operation of the cooling device based on the power information.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 6 ,
The control unit is
Identifying information on a plurality of candidates for a schedule for performing a defrosting operation of the cooling device in the one or more refrigerated warehouses;
displaying the specified information on a display unit in a selectable manner;
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 7 ,
The control unit is
Identifying information on a plurality of candidates for a schedule for performing a defrosting operation of the cooling device in the one or more refrigerated warehouses;
displaying the specified information on a display unit in a selectable manner;
A cold storage warehouse management system characterized by the above. A defrosting determination processing device that can switch between a cooling operation and a defrosting operation and controls a cooling device that adjusts the temperature in a freezer,
A memory unit that stores a reference current value that is a current value of a blower that blows air into the cooling device and serves as a reference for estimating an amount of frost during a cooling operation;
a processor that calculates a difference between a current value of the blower and the reference current value, and performs control to switch from a cooling operation to a defrosting operation when the calculated difference value reaches a predetermined value,
The processor,
updating the reference current value stored in the memory unit based on a current value of the blower during a cooling operation and the reference current value;
The processor,
comparing a first difference value, which is a difference value between the current value of the fan at a predetermined timing and the reference current value, with a second difference value, which is a maximum value of the difference value between the current value of the fan and the reference current value from a cooling operation start point to the predetermined timing;
When the first difference value is smaller than the second difference value by a predetermined threshold value or more, the reference current value is updated to be lower than the previous reference current value.
A defrosting determination processing device characterized by the above . A method for managing a freezer, comprising: controlling a cooling device capable of switching between a cooling operation and a defrosting operation to adjust a temperature in a freezer;
acquiring a current value of a blower that blows air into the cooling device;
calculating a difference between the acquired current value and a reference current value which is a current value of the blower and serves as a reference for estimating an amount of frost formation during a cooling operation, and switching from the cooling operation to a defrosting operation when the calculated difference value reaches a predetermined value;
updating the reference current value based on a current value acquired during a cooling operation and the reference current value ;
a step of comparing a first difference value, which is a difference value between the current value of the fan at a predetermined timing and the reference current value, with a second difference value, which is a maximum value of the difference value between the current value of the fan and the reference current value from a cooling operation start point to the predetermined timing;
and if the first difference value is smaller than the second difference value by a predetermined threshold value or more, updating the reference current value to be lower than the previous reference current value . A refrigerated warehouse management system that controls a cooling device that can switch between a cooling operation and a defrosting operation,
a current measuring unit that measures a current value of a blower that blows air into the cooling device;
A memory unit that stores a reference current value that is a current value of the blower and serves as a reference for estimating the amount of frost during a cooling operation;
A control unit that calculates a difference value between the current value measured by the current measuring unit and the reference current value, and performs control to switch from a cooling operation to a defrosting operation when the calculated difference value reaches a predetermined value,
The control unit is
updating the reference current value stored in the memory unit based on the current value measured by the current measuring unit during a cooling operation and the reference current value;
The control unit is
At the start of a cooling operation, based on a comparison between a current value of the blower and the reference current value, selectively performing one of a process of increasing or decreasing the reference current value;
During the subsequent cooling operation, if the current value of the blower is less than the reference current value, the reference current value is reduced, and if the current value of the blower is equal to or greater than the reference current value, the reference current value is not changed.
A cold storage warehouse management system characterized by the above . The cold storage management system according to claim 12 ,
The control unit is
When the reference current value exceeds a predetermined threshold value, control is performed to notify an administrator by an alarm device that the amount of frost has exceeded a specified amount.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 12 ,
The storage unit is
The updated reference current value is stored.
The control unit is
and controlling a display device to display a time series change in the reference current value.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 12 ,
The control unit is
determining a schedule for performing a defrosting operation of the cooling device based on the estimation result of the current frost state;
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 15 ,
The control unit is
Acquire operation information for one or more cold storage facilities;
and determining a schedule for performing a defrosting operation of the cooling device based on the work information.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 15 ,
The control unit is
Acquire power information for one or more cold storage warehouses;
and determining a schedule for performing a defrosting operation of the cooling device based on the power information.
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 16 ,
The control unit is
Identifying information on a plurality of candidates for a schedule for performing a defrosting operation of the cooling device in the one or more refrigerated warehouses;
displaying the specified information on a display unit in a selectable manner;
A cold storage warehouse management system characterized by the above. The cold storage management system according to claim 17 ,
The control unit is
Identifying information on a plurality of candidates for a schedule for performing a defrosting operation of the cooling device in the one or more refrigerated warehouses;
displaying the specified information on a display unit in a selectable manner;
A cold storage warehouse management system characterized by the above. A defrosting determination processing device that can switch between a cooling operation and a defrosting operation and controls a cooling device that adjusts the temperature in a freezer,
A memory unit that stores a reference current value that is a current value of a blower that blows air into the cooling device and serves as a reference for estimating an amount of frost during a cooling operation;
a processor that calculates a difference between a current value of the blower and the reference current value, and performs control to switch from a cooling operation to a defrosting operation when the calculated difference value reaches a predetermined value,
The processor,
updating the reference current value stored in the memory unit based on a current value of the blower during a cooling operation and the reference current value;
The processor,
At the start of a cooling operation, based on a comparison between a current value of the blower and the reference current value, selectively performing one of a process of increasing or decreasing the reference current value;
During the subsequent cooling operation, if the current value of the blower is less than the reference current value, the reference current value is reduced, and if the current value of the blower is equal to or greater than the reference current value, the reference current value is not changed.
A defrosting determination processing device characterized by the above . A method for managing a freezer, comprising: controlling a cooling device capable of switching between a cooling operation and a defrosting operation to adjust a temperature in a freezer;
acquiring a current value of a blower that blows air into the cooling device;
calculating a difference between the acquired current value and a reference current value which is a current value of the blower and serves as a reference for estimating an amount of frost formation during a cooling operation, and switching from the cooling operation to a defrosting operation when the calculated difference value reaches a predetermined value;
updating the reference current value based on a current value acquired during a cooling operation and the reference current value ;
and selectively performing one of a process of increasing the reference current value and a process of decreasing the reference current value based on a comparison between a current value of the blower and the reference current value at the start of a cooling operation.
During the subsequent cooling operation, if the current value of the blower is less than the reference current value, the reference current value is reduced, and if the current value of the blower is equal to or greater than the reference current value, the reference current value is not changed.
A method for managing a cold storage facility.

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