Refrigerant leakage detection system

Abstract

To provide a refrigerant leakage detection system capable of directly determining the presence or absence of refrigerant leakage by comparing an initial refrigerant amount with a current refrigerant amount without using a complicated process or a complicated system.SOLUTION: The leakage detection system 1 of the refrigerant C in the cooling / heating equipment 2 includes a weight measuring means 15 for measuring the weight of the cooling / heating equipment 2, a control device 17 for storing the weight of the cooling / heating equipment 2 measured by the weight measuring means 15 and determining the leakage of the refrigerant C from the change of the weight, and a communication means 19 for transmitting the determination result of the leakage of the refrigerant C by the control device 17.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a refrigerant leakage detection system for detecting leakage of refrigerant used in air conditioners and other air conditioning equipment, and refrigeration equipment such as freezers. [Background technology]

[0002] Under the Fluorocarbons Emissions Control Law, all commercial refrigeration and air conditioning equipment (Type 1 specified products) is required to undergo a simplified inspection at least once every three months to check for abnormal noise and vibrations in heat exchangers and piping that can be visually inspected, as well as damage to the product's exterior, corrosion, rust, oil stains, etc. Furthermore, based on the amendment to the "Matters that should serve as criteria for judgment by managers of Type 1 specified products" in the Fluorocarbons Emissions Control Law on August 22, 2022, it has become possible to substitute for a simplified inspection if a system that constantly monitors for leaks or malfunctions, etc. (constant monitoring system) that meets the standards is used and the necessary measures are taken to detect leaks or malfunctions early.

[0003] Various systems have been proposed up until now that constantly monitor for leaks or malfunctions, etc., which can replace simple inspections (see, for example, Patent Document 1 and Patent Document 2). The refrigerant leakage detection system described in Patent Document 1 arranges a plurality of temperature sensors and pressure sensors at appropriate positions in the refrigeration cycle, calculates the difference between the actual measured values ​​and the target estimated values, and detects a refrigerant leak when the calculated difference is larger than a predetermined value.

[0004] In addition, the refrigerant leakage detection system described in Patent Document 2, like Patent Document 1, places multiple temperature sensors and pressure sensors at appropriate positions in the refrigeration cycle, calculates a predicted amount of refrigerant leakage during operation or shutdown based on the measured values ​​during operation taken by these sensors, and if this predicted amount exceeds a threshold value, determines whether or not there is a refrigerant leakage and notifies the outside of the determination result. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-002639 A [Patent Document 2] JP 2023-148485 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the refrigerant leak detection systems described in Patent Documents 1 and 2 do not directly detect the amount of refrigerant leakage, but instead determine whether a refrigerant leaks based on temperature changes detected by a temperature sensor and pressure changes detected by a pressure sensor, which is merely an estimate. Therefore, there is a risk that a refrigerant leak may be determined to have occurred even when there are temperature or pressure changes due to other factors, resulting in a somewhat lack of accuracy. Furthermore, determining whether a refrigerant leaks based on temperature and pressure changes requires relatively complex processing, which may result in a complex system.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a refrigerant leak detection system that can directly determine the presence of a refrigerant leak by comparing the initial amount of refrigerant with the current amount of refrigerant, without using complex processing or a cumbersome system. [Means for solving the problem]

[0008] The refrigerant leakage detection system of the present invention that solves the above-mentioned object is a refrigerant leakage detection system for refrigeration equipment, a weight measuring means for measuring the weight of the cooling / heating equipment; a control device that stores the weight of the cooling / heating equipment measured by the weight measuring means and determines whether a refrigerant leaks based on a change in the weight; The device is characterized by comprising at least one of a communication means for transmitting the result of the refrigerant leakage determination made by the control device, and an alarm means for displaying the determination result or issuing an alarm.

[0009] The term "refrigeration equipment" as used herein refers to equipment equipped with a refrigeration cycle that sequentially repeats the four processes of "evaporation," "compression," "condensation," and "expansion," and specifically includes household and commercial air conditioners and air conditioning equipment, industrial refrigeration equipment, freezers, environmental testing equipment, etc. The object measured by the weight measurement means may be the entire refrigeration equipment equipped with the entire refrigeration cycle, or a part equipped with part of the refrigeration cycle, such as the outdoor unit of an air conditioner or freezers.

[0010] The refrigerant leak detection system of the present invention can directly detect refrigerant leaks by measuring the weight of the refrigeration / heating equipment using the weight measurement means, without using complex processes or cumbersome systems such as installing multiple temperature sensors or pressure sensors. Specifically, since a decrease in the weight of the refrigeration / heating equipment can only be attributed to a refrigerant leak, a refrigerant leak is detected based on the decrease in the weight of the refrigeration / heating equipment. Furthermore, by including the communication means and transmitting the refrigerant leak detection results to a system administrator, person in charge, or repair shop, the system can be used as a continuous monitoring system that can replace simple inspections.

[0011] In the refrigerant leakage detection system of the present invention, the weight measuring means may be disposed between the outdoor unit of the refrigeration equipment and an installation surface of the outdoor unit.

[0012] Here, the weight measuring means may be a load cell.

[0013] By adopting a configuration in which the weight measuring means is disposed between the outdoor unit of the refrigeration / heating equipment and the installation surface of the outdoor unit, it becomes possible to install the weight measuring means as an add-on without making any modifications to the existing refrigeration / heating equipment.

[0014] Furthermore, in the refrigerant leakage detection system of the present invention, the weight measuring means measures the weight of the refrigeration / heating equipment multiple times at predetermined time intervals, In another preferred embodiment, the control device calculates an average value of the weight of the refrigeration equipment measured by the weight measuring means for each predetermined time period, and determines whether or not there is a refrigerant leak based on a change in the average value.

[0015] Here, the average value may be calculated using a median moving average, but it is preferable to use a backward moving average, which is suitable for real-time processing.

[0016] By adopting this method, it is possible to minimize the influence of weight changes unrelated to refrigerant leakage, which may affect the measurement of the weight of the refrigeration / heating equipment, caused by external factors such as wind, compressor vibration, snow accumulation on the refrigeration / heating equipment, animals such as cats standing on the equipment, or placing luggage on the equipment.

[0017] Furthermore, in the refrigerant leak detection system of the present invention, the control device may calculate the amount of refrigerant lost from the change in weight of the refrigeration equipment, output a warning if the value exceeds a first threshold, and determine that an error has occurred if the value exceeds a second threshold that is higher than the first threshold.

[0018] The revised Fluorocarbons Recovery and Destruction Act of 2022 requires, as a standard for continuous monitoring systems, that it be confirmed that leakage can be detected before 30% of the appropriate filling amount of refrigerant leaks. Therefore, the first threshold value may be set to 15% of the total amount of refrigerant, and the second threshold value may be set to 30% of the total amount of refrigerant.

[0019] By adopting this aspect, the extent of the refrigerant leakage can be determined clearly and quickly, and the next steps, such as repairs or equipment replacement, can be smoothly taken.

[0020] Furthermore, in the refrigerant leak detection system of the present invention, the communication means may transmit the weight of the refrigeration equipment measured by the weight measurement means together with the determination result to a server such as a data center or an in-house network.

[0021] Here, the data transmitted by the communication means may be configured to be transmitted to a server in a data center or an in-house network via a telephone line such as 3G, 4G, or 5G, an internet line, a wired or wireless dedicated line, or the like, and further transmitted to a terminal such as a PC, smartphone, or tablet of a system administrator, person in charge, or repair technician. [Effects of the Invention]

[0022] According to the present invention, a refrigerant leak detection system can be provided that can directly determine whether a refrigerant leaks by comparing the initial amount of refrigerant with the current amount of refrigerant, without using complex processing or a cumbersome system. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram conceptually showing the refrigeration cycle of a cooling and heating device (commercial air conditioner) to which the refrigerant leakage detection system of the present invention is applied. [Figure 2] 1 is a schematic diagram showing a refrigerant leak detection system of the present invention. [Figure 3] 10 is a flowchart showing an example of a flow of calculating a weight average value of a cooling / heating device. [Figure 4] 4 is a flowchart showing a procedure for determining whether a refrigerant leaks. [Figure 5] 10 is a graph showing the relationship between the change in weight of the refrigerant and the first and second threshold values. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The refrigerant leak detection system of the present invention is not particularly limited to refrigeration equipment equipped with a refrigeration cycle, and can be applied to refrigerant leak detection in, for example, home or commercial air conditioners and air conditioning equipment, industrial refrigeration equipment, freezers, environmental testing equipment, etc. In the following example, a commercial air conditioner will be used as an example of refrigeration equipment. In addition to fluorocarbons, examples of refrigerants include ammonia, carbon dioxide, and propane.

[0025] Fig. 1 is a conceptual diagram showing the refrigeration cycle of a cooling and heating device (commercial air conditioner) 2 to which a refrigerant leak detection system 1 (see Fig. 2) of the present invention is applied. In Fig. 1, the flow of refrigerant C is indicated by arrows, with refrigerant C in hatched pipes being in a high temperature state and refrigerant C in unhatched pipes being in a low temperature state.

[0026] As shown in Fig. 1, the refrigeration equipment 2 includes an outdoor unit 2A having a compressor, a pressure reducer, a heat exchanger, etc., and an indoor unit 2B having a heat exchanger, etc., and has a refrigeration cycle in which a refrigerant C circulates through these. As will be described in detail later, this embodiment employs a configuration in which leakage of the refrigerant C is detected by measuring the weight of the outdoor unit 2A. Note that, when measuring the weight of the outdoor unit 2A, the weight of the entire outdoor unit 2A may be measured, but because the compressor in the outdoor unit 2A is overwhelmingly heavy and has a large impact, it may also be possible to measure the weight of the part where the compressor is located (the left side in Fig. 1).

[0027] FIG. 2 is a schematic diagram showing a refrigerant leak detection system 1 of the present invention.

[0028] As shown in Figure 2, the refrigerant leak detection system 1 of the present invention is a system that obtains a change in the weight M of the refrigerant C by comparing the initial weight M0 of the refrigeration equipment 2 immediately after it is filled with refrigerant C with the current weight M of the refrigeration equipment 2 when the refrigeration equipment 2 is being used, and detects a leak of refrigerant C from the obtained change in the weight M of the refrigerant C, enabling stable daily operation of the refrigeration equipment 2 and prompt response such as repair or equipment replacement. The initial weight M0 of the refrigeration equipment 2 may be the weight before operation begins when the refrigeration equipment 2 is newly installed, or it may be the weight immediately after it is refilled with refrigerant C.

[0029] In addition, the refrigerant leakage detection system 1 of the present invention is specifically configured to include a weight measurement means 15 that measures the weight M of the refrigeration equipment 2, a control device 17 that stores the measured weight M of the refrigeration equipment 2 and determines whether or not there is a leakage of the refrigerant C from changes in the weight M, and a communication means 19 that transmits the data stored by the control device 17 and the determination result to a user or a system administrator, etc.

[0030] The weight measuring means 15 of this embodiment is composed of a load cell 16 disposed between the outdoor unit 2A and its installation surface GL. The functions of the control device 17 and the communication means 19 are executed by a single IoT terminal 21.

[0031] The data transmitted by the communication means 19 is sent to a server 25 such as a data center 23 or an in-house network via a telephone line such as 3G, 4G, or 5G, an internet line, a wired or wireless dedicated line, or the like, and stored there. The data is then sent to a terminal such as a PC 27, a smartphone 29, or a tablet 31 of a system administrator, person in charge, or repair technician, and can be viewed there. This allows the status of refrigerant C leakage to be checked at any time from a remote location without having to visit the site.

[0032] FIG. 3 is a flowchart showing an example of the flow of calculating the weight average value MA of the cooling / heating equipment 2.

[0033] In the refrigerant leakage detection system 1 of the present invention, the weight M of the refrigeration equipment 2 is measured multiple times at predetermined intervals using a load cell 16, and the control device 17 calculates the average weight value MA, and determines whether or not there is a leakage of the refrigerant C from the change in the average weight value MA.

[0034] 3, the weight M of the outdoor unit 2A of the cooling / heating equipment 2 is measured every hour (step S11), and the weight average value MA of the cooling / heating equipment 2 for five measurements from the n-4th time to the nth time is calculated based on the backward moving average method (step S12) as shown in Equation 1. Then, the calculated weight average value MA is stored in the memory of the control device 17 (step S13), and is also transmitted to the data center 23, the in-house network, etc.

[0035] [Math 1]{M(n-4)+M(n-3)+M(n-2)+M(n-1)+M(n)} / 5

[0036] In this way, by using the weight average value MA, it is possible to minimize the effects of weight changes that are unrelated to refrigerant leakage, such as those caused by external factors such as wind, compressor vibration, snow accumulation on the refrigeration equipment 2, or the presence of animals such as cats or luggage on the equipment.

[0037] FIG. 4 is a flowchart showing the flow of refrigerant leakage determination, and FIG. 5 is a graph showing the relationship between the transition of the refrigerant weight and the first and second threshold values.

[0038] In the refrigerant leakage detection system 1 of this embodiment, as an example, the control device 17 is configured to calculate the amount of decrease in refrigerant C from the change in weight M of the cooling / heating equipment 2, and to issue an alarm if the value exceeds a first threshold value A, which is, for example, 15% of the total amount of refrigerant C, and to determine that an error has occurred if the value exceeds a second threshold value B, which is, for example, 30% of the total amount of refrigerant C.

[0039] Here, the amount of refrigerant C lost may be calculated by, for example, using the difference between the weight of the outdoor unit 2A when all of the refrigerant C has been recovered from the installed refrigeration equipment 2 and the weight of the outdoor unit 2A when the refrigerant C is filled into the refrigeration equipment 2 as the initial weight of refrigerant C, and calculating the amount of refrigerant C lost from this initial weight. Furthermore, when a refrigeration equipment 2 is newly installed, the initial weight of refrigerant C may be calculated by using the difference between the weight of the outdoor unit 2A installed when filled with refrigerant C and the catalog value or other value of the weight of the outdoor unit 2A excluding the refrigerant C.

[0040] As shown in FIG. 4, in this embodiment, the calculated weight average value MA of the cold heating and cooling equipment 2 is compared with the initial weight M0 of the cold heating and cooling equipment 2 to determine the amount of reduction in the refrigerant C (step S21).

[0041] Next, as also shown in Figure 5, a determination is made as to whether the obtained amount of reduction in refrigerant C exceeds a first threshold A (e.g., 15% of the total amount of refrigerant C) (step S22), and if it exceeds the first threshold A, a determination is made as to whether the amount of reduction in refrigerant C exceeds a second threshold B (e.g., 30% of the total amount of refrigerant C) (step S23).

[0042] If it is determined in S23 that the second threshold B is not exceeded, a warning is output (step S24) and is notified to a terminal such as PC 27, smartphone 29, or tablet 31 of a system administrator, person in charge, or repairer, etc. This can prompt the system administrator, etc. to take action (such as repairing or replacing the cooling / heating device 2).

[0043] Furthermore, if the response is not made in time and it is determined in S23 that the second threshold B has been exceeded, it is determined to be an error (step S24), and emergency processing is carried out, such as stopping the operation of the cooling / heating equipment 2, along with notifying the system administrator, etc.

[0044] If it is determined in S22 that the amount of decrease in refrigerant C does not exceed the first threshold value A, the process continues to monitor for leakage of refrigerant C (step S26).

[0045] Although not related to the leakage of refrigerant C, if the increase in weight of the refrigeration equipment 2 exceeds a predetermined threshold, the system administrator or the like may be notified, and external factors such as whether there is snow on the refrigeration equipment 2 or whether there are animals or cargo on it may be checked, and measures to remove the external factors may be taken.

[0046] According to the refrigerant leakage detection system 1 of the present invention described above, it is possible to directly determine whether or not there is a leakage of refrigerant C by comparing the initial amount of refrigerant C with the current amount of refrigerant C, without using complex processing or a cumbersome system.

[0047] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. For example, the weight measurement means 15 that detects the weight of the refrigeration equipment 2 is not limited to a load cell, and other types of weigh scales or weight sensors may be used. Furthermore, the measurement interval for determining the average weight value MA of the refrigeration equipment 2 is not limited to one hour, and may be set shorter or longer, and the number of measurements is not limited to five.

[0048] Furthermore, the first threshold A at which a warning is issued is not limited to 15% of the total amount of refrigerant C, but can be set to another ratio, such as 10% or 20% of the total amount of refrigerant C. However, in order to satisfy the requirement for continuous monitoring systems under the revised Fluorocarbons Emissions Control Act of 2022 that a leak be detected before 30% of the appropriate filling amount of refrigerant leaks, a warning must be issued at least before the total amount of refrigerant C is leaked.

[0049] The second threshold B at which an error is determined is not limited to 30% of the total amount of refrigerant C, but can be set to another ratio, such as 25% or 35% of the total amount of refrigerant C. Note that an error can also be determined without issuing a warning, but in that case, in relation to the aforementioned revised 2022 Fluorocarbons Emission Control Act, it is preferable to determine an error before the amount reaches 30% of the total amount of refrigerant C.

[0050] Furthermore, as a means of communication when a warning or error occurs, in addition to or instead of sending to a terminal such as the aforementioned PC 27, smartphone 29 or tablet 31, the cooling / heating equipment 2 (outdoor unit 2A or indoor unit 2B) may be provided with a lamp or the like that displays a warning or error, or with an alarm means that issues an alarm such as a voice or buzzer sound.

[0051] In addition, if a temperature sensor, a pressure sensor, or the like is already installed in the refrigeration equipment 2, the results of the refrigerant leakage detection system 1 may be confirmed from data measured by these sensors. [Explanation of symbols]

[0052] 1 Refrigerant leak detection system 2 Cooling equipment 2A outdoor unit 2B indoor unit 15 Weight measurement means 16 load cells 17 Control device 19. Means of communication 21 IoT devices 23 Data Centers 25 servers 27 PC 29 Smartphone 31 tablets C Refrigerant GL installation surface M weight MA (weight) average value A. First Threshold B. Second Threshold

Claims

1. A refrigerant leakage detection system for refrigeration equipment, a weight measuring means for measuring the weight of the cooling / heating equipment; a control device that stores the weight of the cooling / heating equipment measured by the weight measuring means and determines whether a refrigerant leaks based on a change in the weight; A refrigerant leak detection system comprising at least one of a communication means for transmitting the refrigerant leak determination result by the control device, and an alarm means for displaying the determination result or issuing an alarm.

2. 2. The refrigerant leakage detection system according to claim 1, wherein the weight measuring means is disposed between an outdoor unit of the refrigeration equipment and a surface on which the outdoor unit is installed.

3. the weight measuring means measures the weight of the cooling / heating equipment multiple times at predetermined time intervals, 3. The refrigerant leakage detection system according to claim 1, wherein the control device calculates an average value of the weight of the refrigeration equipment measured by the weight measuring means for each predetermined time period, and determines whether or not there is a refrigerant leakage based on a change in the average value.

4. The refrigerant leak detection system according to claim 1 or 2, characterized in that the control device calculates the amount of refrigerant lost from the change in weight of the refrigeration equipment, outputs a warning if the calculated value exceeds a first threshold, and determines that an error has occurred if the calculated value exceeds a second threshold that is higher than the first threshold.

5. 3. The refrigerant leak detection system according to claim 1, wherein the communication means transmits the weight of the refrigeration equipment measured by the weight measuring means together with the determination result to a server in a data center, an in-house network, or the like.

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