JP7519962B2 - Cooling system, defrost determination system, and defrost determination method - Google Patents

Description

The present invention relates to a cooling system, a defrost determination system, and a defrost determination method.

According to Patent Document 1, "It is characterized by having a cooler temperature detection means 12a for detecting the temperature of the cooler, a cooler ambient temperature detection means 12b for detecting the ambient temperature of the cooler, and a frost amount prediction processing means 16 for predicting the amount of frost on the cooler from the detection information of both the cooler temperature detection means 12a and the cooler ambient temperature detection means 12b and determining the timing of defrosting" (see abstract).

According to Patent Document 2, "The energy saving management device (10) estimates the temperature distribution in the low-temperature warehouse (2) by performing airflow analysis and an operation simulation of the air conditioner (20). The energy saving management device (10) determines improvements to the air conditioner (20) for energy saving based on the estimated temperature distribution. The energy saving management device (10) estimates the power consumption of the air conditioner (20) after the improvement points are applied by performing airflow analysis and an operation simulation of the air conditioner (20) after the improvement points are applied. The energy saving management device (10) calculates the electricity charge reduced by applying the improvement points as the energy saving effect based on the power consumption of the air conditioner (20) before the improvement, the estimated power consumption of the air conditioner (20) after the improvement, and charge table information, which is information on the electricity charge table" (see abstract).

Japanese Patent Application Publication No. 10-227555 WO2020/8550 publication

Patent Document 1 discloses a technology that detects the temperature of a cooler and the temperature around the cooler, predicts the amount of frost, and determines the timing of defrosting. However, unlike household refrigerators and freezers, commercial cold storage warehouses are subject to complex frost conditions that are difficult to predict, as not only the outside temperature but also the outside humidity can easily flow into the cold storage warehouse and there is a high volume of goods coming in and out.

Patent Document 2 discloses a technology that estimates the temperature distribution in a low-temperature warehouse by performing airflow analysis and air-conditioning simulation using layout air-conditioning information of the low-temperature warehouse and information on the incoming and outgoing cargo entering and leaving the low-temperature warehouse, identifies improvements to the air-conditioning equipment to save energy, and calculates the energy-saving effect based on power consumption before and after the improvements are applied. It also discloses that humidity information is used when identifying improvements. Furthermore, freezer warehouses are also considered as low-temperature warehouses, and it is disclosed that the occurrence of frost and mold is prevented by applying a lot of air from the air conditioner to high humidity areas to prevent these from occurring.

Therefore, in both Patent Documents 1 and 2, the frost state cannot be calculated accurately, making it difficult to optimize the defrosting process of a refrigerated warehouse from the perspective of energy efficiency.

The objective of the present invention is to optimize defrosting processes in cold storage warehouses from the perspective of energy efficiency.

The cooling system of one aspect of the present invention is characterized by having an imaging device that images the frosted area, an image analysis device that calculates information about the amount of frost from the image captured by the imaging device, and a control unit that determines the timing of performing a defrost process based on the calculated information about the amount of frost.

According to one aspect of the present invention, it is possible to optimize the defrosting process in a refrigerated warehouse from the perspective of energy efficiency.

FIG. 1 is an image diagram of a refrigerated warehouse management system according to the present invention. FIG. 1 is an image diagram of a refrigerated warehouse according to the present invention. FIG. 1 is a diagram showing an example of a system block diagram of a refrigerated warehouse management system according to the present invention. FIG. 2 is a conceptual diagram of an imaging device and an image analyzing device according to the present invention. 4 is a flowchart at the start of a defrosting process according to the present invention. 5 is a flowchart showing the process at the end of the defrosting process according to the present invention. FIG. 2 is an image diagram of a cooler and heat dissipation fins of the present invention.

As a general rule, explanations of identical or similar parts will not be repeated unless specifically necessary. Even if the reference numerals shown in a given figure are used to explain other figures, explanations of identical or similar parts will be omitted.

In the following embodiments, for convenience, when necessary, the description will be divided into multiple sections or embodiments, but unless otherwise specified, they are not unrelated to each other, and one is related to the other in terms of partial or complete modifications, details, supplementary explanations, etc.

In the following embodiments, when referring to the number of elements (including the number, numerical value, amount, range, etc.), unless otherwise specified or clearly limited in principle to a specific number, it is not limited to that specific number and may be more than or less than the specific number.

In the following embodiments, the "input/output unit" includes one or more interfaces. The one or more interfaces may be one or more interface devices of the same type or two or more interface devices of different types.

In the following embodiments, a "storage unit" includes one or more memories. At least one memory in the storage means may be a volatile memory. The storage unit is mainly used during processing by the processor unit. In addition to the memory, the storage unit may include one or more non-volatile storage devices (e.g., a hard disk drive (HDD) or a solid state drive (SSD)).

In the following embodiments, the "control unit" includes one or more processors. At least one processor is typically a microprocessor such as a CPU (Central Processing Unit), but may be other types of processors such as a GPU (Graphics Processing Unit). Each of the one or more processors may be single-core or multi-core. The processor may include a hardware circuit that performs some or all of the processing.

In the following embodiments, functions are sometimes described using the expression "kkk unit" (excluding the interface unit, memory unit, and control unit), but the functions may be realized by one or more computer programs (excluding the control program and information program described below) being executed by the control unit, or may be realized by one or more hardware circuits (e.g., an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit)).

When a function is realized by a program being executed by a processor unit, the defined processing is performed using a storage unit and/or an interface unit, etc., as appropriate, and therefore the function may be considered to be at least a part of the processor unit. Processing described using the function as the subject may be considered to be processing performed by the processor unit or a device having the processor unit.

The program may be installed from a program source. The program source may be, for example, a program distribution computer or a computer-readable recording medium (for example, a non-transitory recording medium). The description of each function is an example, and multiple functions may be combined into one function, or one function may be divided into multiple functions.

In the following explanation, information that produces an output for an input may be described using expressions such as "xxx table," but the information may be data of any structure, or may be a learning model such as a neural network that produces an output for an input. Therefore, a "xxx table" can be called "xxx information." In the following explanation, the structure of each table is an example, and one table may be divided into two or more tables, or two or more tables may all or partly be one table.

It goes without saying that in the following embodiments, the components (including element steps, etc.) are not necessarily essential unless specifically stated otherwise or considered to be clearly essential in principle.

The following describes an embodiment of the present invention with reference to the drawings.

FIG. 1 is a conceptual diagram of a refrigerated warehouse management system according to the present invention.
The cold storage management system 100 has a cold storage 110, which is provided with an entrance/exit 120, which is a door through which goods are carried in and out by a transport means 130. Information on the time when the transport means 130 carries goods in and out of the cold storage 110 and the transport targets are stored and managed by a transport management unit 160. The transport means may be a truck or a trailer.

The management system 140 controls a turbo compressor or a screw compressor, which are typical examples of coolers installed in the cold storage warehouse 110. Hereinafter, they will be simply called coolers, turbo compressors, or screw compressors, but are not limited to these and may be any type of cooler. They may also be called turbo coolers or screw coolers. The screw coolers are controlled by the management system 140 based on temperature sensors and humidity sensors installed inside the cold storage warehouse 110, or frost detection means installed around the coolers, meteorological information 150, and information stored in the transport management unit 160. A specific control method will be described later.

FIG. 2 is an image diagram of a refrigerated warehouse according to the present invention.
1. A detailed diagram of the refrigerated warehouse 110 and the entrance/exit 120 of the refrigerated warehouse 110 is shown in FIG.

A goods handling room 220 is provided at the loading/unloading entrance 120. The goods handling room 220 is provided with a berth 210 where a transport means 130 arrives and departs to transport goods to and from the refrigerated warehouse 110, and a temporary storage area 230 where goods are temporarily stored from the berth 210. A loading/unloading opening 240 is provided between the goods handling room 220 and the low-temperature area 250, and goods can be transported by transport means such as a forklift or AGV (Automated Guided Vehicle). The refrigerated warehouse 110 is opened to the outside air or the goods handling room 220, so that a temperature rise is unlikely to occur.

Conventionally, the berth 210 is opened every time the transport means 130 arrives, and when it is opened, the material handling room 220 is exposed to outside air, which increases the temperature and humidity inside the material handling room 220. In addition, as the temperature and humidity inside the material handling room 220 increase, when goods are transported from the material handling room 220 to the low-temperature area 250, the temperature and humidity in the low-temperature area 250 also increase. Therefore, it is advisable to reduce the number of times and the time for which the berth 220 and the loading/unloading opening 240 are opened.

In the above-mentioned freezer warehouse 110, when the cooler compresses the air and circulates the cooled air, the heat dissipation fins become cold, so the moisture in the air around the fins freezes and sticks to the fins, causing frost to form on the fins. If the humidity or moisture content inside the freezer warehouse 100 increases, frost will form on the fins more easily. Therefore, to make it difficult for moisture in the outside air to enter the freezer warehouse, or to keep the humidity inside the freezer warehouse as low as possible, it is advisable to open the loading/unloading opening 240 less frequently or for a shorter period of time. The task of removing the frost that has stuck to the fins in this way (also simply called frost) is called defrosting or defrosting.

The defrosting method may be a method in which the fins are heated with an electric heater, a hot gas method in which warm exhaust gas is applied, or a water spraying method in which warm water is sprayed on the cooler.

Next, the system block diagram of the defrost control system for a refrigerated warehouse according to the present invention will be described with reference to FIG.
The management system 140 has an input/output unit 330, a control unit 310, and a storage unit 320. The input/output unit 330 may have a user interface such as a keyboard or a mouse, or may be an input/output unit integrated with a display unit such as a touch panel. It may also be an input/output unit accessible via a network.

Information on the current value and applied voltage value when operating the fan of the cooler 340 arranged in the cold storage warehouse 110, the intake/exhaust temperature and amount of frost for the air sucked in and blown out by the cooler fan are input via the input/output unit 330 of the management system 140. The amount of frost will be described later. Based on this input information, the management system 140 controls the screw refrigerator that cools the cold storage warehouse 110. In addition, it can also generate and manage an operation schedule for the entire cold storage warehouse 110, taking into account not only the screw refrigerator but also the overall efficiency. The control method and operation schedule will be described later.

The management system 140 may be configured to control one cooler 340 installed in one freezer warehouse 110, or may be configured to control both coolers 340, 341 when multiple coolers are installed in one freezer warehouse 110. There may be a single cooler as a cooling device with multiple air outlets and fins as coolers. In addition, when there are multiple freezer warehouses 110, 111 at one base or the like, or when multiple freezer warehouses in remote locations are controlled by one management system, the management system 140 may be configured to control multiple freezers installed in those multiple freezer warehouses and their defrost control. When they are in remote locations, the management system 140 may be installed on the cloud.

Next, information on the current value, the voltage value, the intake/exhaust temperatures, and the amount of frost that is input from the cooler 340 to the input/output unit 330 will be described with reference to FIG.
To detect the amount of frost, the frost adhering to the cooler 340 is photographed by the camera 410 and input to the image analysis system 420. The image analysis system 420 may be provided in the management system 140. An image of a predetermined range including the frost is stored in the storage unit 440. The image analysis system 420 digitizes the image data of the frost input to the storage unit 440.

As shown in FIG. 7, the cooler 340 is composed of a housing and fins, and although frost may form thinly over the entire surface, the area of frost may spread from the side closer to the loading/unloading opening 240, which is the side of the freezer warehouse 110 with a higher moisture content. Therefore, in order to capture the effect of frost on the cooling performance of the fins of a cooler with a large area, the camera 410 does not have to be located directly in front of the fins, but is preferably installed so that the entire surface, or at least a large portion of it, is included in the imaging range.

The image data values may be calculated based on the cumulative values of the pixels capturing the entire fin, regardless of whether the areas are frosted or not, or the frosted areas may be identified and calculated based on the percentage of that area or the pixel detection values of the area.

The captured image can also be converted to grayscale and the amount of frost can be identified based on the brightness of the grayscale. The greater the amount of frost, the larger the value. In addition, if a relationship can be identified in which the numerical value simply increases or decreases as the amount of frost increases by performing image processing to separate the color of the fins from the color of the frost, information regarding the amount of frost can be identified using methods other than those mentioned above.

For example, inside the freezer warehouse 110, the area around the fins may be dark, and the environment may not necessarily be suitable for imaging. In this case, lighting may be applied from a specific angle to the imaging angle that includes the fins, and information regarding the amount of frost may be identified using the difference between the illuminated and unilluminated conditions. Alternatively, the color of the frost may be extracted in HSV space to identify the amount of frost.

The amount of frost can also be determined by fixing the imaging means, using an image without frost as a reference, convolving the reference frost-free image from the captured image pixel by pixel, or convolving specific surrounding pixels taking into account errors in the imaging position due to compressor vibration, fitting the reference positions together, and then obtaining the difference.

The information regarding the amount of frost quantified by the image analysis system 420 is stored in the memory unit 440, and the stored information regarding the amount of frost is input to the management system 140 via an input/output unit and an input/output unit 330 of the image analysis system 420 (not shown).

Next, the current value, voltage value, and intake/exhaust temperature are input to the data collection system 430 via sensor information attached to the cooler 340. The sensors that acquire these values may be built into the cooler 340, or may be separately attached to the periphery of the cooler 340.

The acquired sensor information of the cooler 340 is taken in by the data collection system 420, and this information is taken in by the management system 140 via the input/output unit 330. The data collection system 140 may be built into the control means of the cooler, in which case it can be directly interfaced with the management system 140. In addition, it can be implemented by using control devices such as a PLC (Programmable Logic Controller), an IPC (Industrial Personal Computer), or an IoT (Internet of Things) controller between the cooler 340 and the management system 140.

Based on this captured sensor information, the management system 140 controls the refrigeration unit 340, determines the timing of defrosting, and creates an operation schedule for the cold storage warehouse 100.

Next, a flow until the defrost control is turned ON will be described with reference to FIG.
After processing the data input (step 510), management system 140 determines if a system error has occurred (step 520).

If an error occurs, the system transitions to conventional control mode (step 530). If no error occurs, the system transitions to calculation processing (step 540).

From the values calculated in the calculation process (step 540), it is determined whether the current value exceeds a preset upper threshold (step 550), whether the intake/exhaust temperature difference exceeds a preset lower threshold (step 560), whether the amount of frost quantified by the image analysis system 420 exceeds a preset upper threshold (step 570), and whether the time during which defrost has not yet been operated, calculated by the management system 140 as the time elapsed since the completion of the previous defrost operation, exceeds a preset upper threshold (step 580).

If the conditions are met in either of the determination processes, the defrost control is turned on (step 511). If the conditions are not met in either of the determination processes, no signal is output (step 590).

Here, the above threshold parameters can be manually changed. Also, the judgment period can be set to, for example, every minute.

Next, a flow until the defrost control is turned OFF will be described with reference to FIG.
After processing the data input (step 510), the management system 140 determines whether a system error has occurred (step 520). If an error has occurred, the system transitions to the conventional control mode (step 530). If no error has occurred, the system transitions to calculation processing (step 540).

The value calculated in the calculation process 540 is used to determine whether the amount of frost is below a preset lower threshold (step 610) or whether the defrost continuation operation time exceeds a preset upper threshold (step 620). If the condition is met in either determination process, the defrost control is turned OFF (step 640). If the condition is not met in either determination process, no signal is output (step 630).

The above threshold parameters can be manually changed. The judgment period is preferably, for example, once a minute.

When multiple coolers are installed in the freezer warehouse 110, different thresholds for the amount of frost can be set in advance in the management system 140 for coolers 340 and 341. This allows optimal control when the susceptibility to frost differs depending on installation conditions such as the relative positions of the coolers 340 and 341 with respect to the loading and unloading openings.

Similarly, different thresholds can be set for the defrost no operation time and the defrost continuous operation time. It is particularly desirable to set a lower threshold so that the defrost frequency is higher for the cooler closer to the loading/unloading entrance, and this allows the management system 140 to control the defrost by setting the defrost frequency higher on the side closer to the loading entrance.

Furthermore, when defrosting multiple coolers in the same freezer warehouse 110, or when there are multiple freezer warehouses at the same site, the defrosting can be performed at different times, or at least not simultaneously, preferably by performing the defrosting process under the condition that the other defrosting process is not in operation, or by setting conditions in the calculation process 540 to permit defrosting after a predetermined time has elapsed after the other defrosting process.

This allows the period of increased power consumption due to defrosting to be staggered, smoothing out power consumption. Also, although cooling capacity decreases during defrosting, by staggering the effect of this by a specified period across multiple coolers installed in the same freezer warehouse, it is possible to suppress temperature changes inside the warehouse.

The cold storage management system of the above embodiment uses an imaging device to capture an image of an area including heat dissipation fins attached to a cooler, and quantifies the frosting state by analyzing the image. By determining the timing to perform a defrosting process based on the calculated numerical value, it is expected that the operational efficiency of the cold storage as a whole can be improved.

In this way, according to the above embodiment, the frost that has formed around the cooler can be identified based on the frost condition and the operational status of the refrigerated warehouse, and defrosting processing can be performed, thereby increasing the operational efficiency of the entire refrigerated warehouse.

The present invention is not limited to the above-described embodiments, but includes various modified examples and equivalent configurations within the spirit of the appended claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to having all of the configurations described. Furthermore, a portion of the configuration of one embodiment may be replaced with the configuration of another embodiment. Furthermore, the configuration of another embodiment may be added to the configuration of one embodiment. Furthermore, other configurations may be added, deleted, or replaced with part of the configuration of each embodiment.

For example, in the above-mentioned embodiment, the defrosting work has been described as the work of removing frost that has adhered to the fins, but the present invention is not limited to the work of defrosting the fins, and can also be applied to the work of removing frost that has adhered to parts other than the fins.

Furthermore, each of the configurations, functions, processing units, processing means, etc. described above may be realized in part or in whole in hardware, for example by designing them as integrated circuits, or may be realized in software by a processor interpreting and executing a program that realizes each function.

Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, hard disk, or SSD (Solid State Drive), or in a recording medium such as an IC card, flash memory, or DVD.

In addition, the control lines and information lines shown are those considered necessary for explanation, and do not necessarily represent all control lines and information lines necessary for implementation. In reality, it is safe to assume that almost all components are interconnected.

Reference Signs List 100 Refrigerated warehouse management system 110 Refrigerated warehouse 120 Intake/outlet gate 130 Transport means 140 Management system 310 Control means 320 Memory means 220 Handling room 230 Temporary storage area 240 Carry-in/outlet gate 340 Cooler 410 Frost state monitoring camera 420 Image analysis system 430 Data collection system

Claims (6)

An imaging device for imaging the frosted area;
An image analyzer that calculates information regarding the amount of frost from the image captured by the imaging device;
A control unit that determines the timing of performing a defrost process based on information about the calculated amount of frost;
having
The imaging device includes:
An image of an area including a heat dissipation fin attached to a cooler is taken as the frosted area,
The control unit is
determining whether or not a current value flowing through the fan of the cooler exceeds a first upper limit threshold value set in advance, and performing the defrosting process when the current value exceeds the first upper limit threshold value;
When the current value does not exceed the first upper threshold, it is determined whether or not a temperature difference between an intake temperature and a discharge temperature of the cooler exceeds a preset lower threshold, and when the temperature difference exceeds the lower threshold, the defrost process is performed;
When the temperature difference does not exceed the lower limit threshold, it is determined whether or not the amount of frost exceeds a second upper limit threshold set in advance, and when the amount of frost exceeds the second upper limit threshold, the defrost process is performed;
A cooling system characterized in that, when the amount of frost does not exceed the second upper limit threshold, it determines whether a duration of no defrost operation exceeds a preset third upper limit threshold, and performs the defrost operation when the duration of no defrost operation exceeds the third upper limit threshold, thereby identifying the timing to perform the defrost operation . A cooling system for determining the defrosting process for a plurality of coolers,
The frost amount threshold is preset for each of the plurality of coolers,
The cooling system of claim 1 , wherein the threshold value varies depending on the cooler. A cooling system for determining the defrosting process for a plurality of coolers,
The plurality of cooling devices are installed in the same freezer warehouse,
The control unit is
The cooling system according to claim 1 , wherein the defrosting process is controlled so that the defrosting process of each of the plurality of coolers is performed at a different time. The imaging device includes:
The cooling system according to claim 1 , wherein the cooler is installed so that the entire surface of the cooler is included in the imaging range as the frosted area. The cooling system according to claim 1 , further comprising a lighting device arranged so that light is directed onto the cooler. An image acquisition step of acquiring an image of the frosted region;
A calculation step of calculating information regarding the amount of frost from the image;
A determination step of determining the timing to perform a defrost process based on information about the calculated amount of frost;
having
The determining step includes:
determining whether or not a current value flowing through a fan of the cooling device exceeds a first upper limit threshold value set in advance, and performing the defrosting process when the current value exceeds the first upper limit threshold value;
When the current value does not exceed the first upper threshold, it is determined whether or not a temperature difference between an intake temperature and a discharge temperature of the cooler exceeds a preset lower threshold, and when the temperature difference exceeds the lower threshold, the defrost process is performed;
When the temperature difference does not exceed the lower limit threshold, it is determined whether or not the amount of frost exceeds a second upper limit threshold set in advance, and when the amount of frost exceeds the second upper limit threshold, the defrost process is performed;
A defrost determination method characterized by determining whether a duration of no defrost operation exceeds a preset third upper limit threshold when the amount of frost does not exceed the second upper limit threshold, and performing the defrost operation when the duration of no defrost operation exceeds the third upper limit threshold, thereby identifying the timing to perform the defrost operation .

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