Refrigerant leakage detector

Abstract

To disclose one example of a refrigerant leakage detector capable of detecting leakage of a refrigerant even when a state where a compressor is in a stopped state for a long time has occurred.SOLUTION: When a value obtained by subtracting detection pressure Pi(n) from reference pressure Pi(m) becomes a predetermined value or higher, a determination device determines occurrence of leakage of a refrigerant. A start day means a day when a compressor starts from a state where the compressor is in a stopped state continuously for 24 hours or longer. The reference pressure Pi(m) means pressure detected by a pressure sensor S1 when the compressor is in a stopped state at the start day. The detection pressure Pi(n) means pressure detected by the pressure sensor S1 in the stopped state when the stopped state of the compressor continues for 24 hours or longer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a refrigerant leak detection device that detects whether or not a refrigerant circulating inside a vapor compression refrigerator is leaking from the vapor compression refrigerator. [Background technology]

[0002] In seasons such as winter when a large cooling capacity is not required, the compressor stops for a long time. When the compressor is stopped, the refrigerant pressure in each part of the vapor compression refrigerator becomes approximately equal, making it difficult to detect a refrigerant leak using pressure changes.

[0003] In contrast, in the vapor compression refrigerator described in Patent Document 1, the refrigerant pressure when the compressor is stopped is compared with an estimated refrigerant pressure calculated based on the outside air temperature to determine whether a refrigerant leak has occurred. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-241050 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure discloses an example of a refrigerant leak detection device that can detect a refrigerant leak even when a state occurs in which a compressor is stopped for a long period of time. [Means for solving the problem]

[0006] A refrigerant leakage detection device that detects whether or not refrigerant circulating inside a vapor compression refrigerator is leaking from the vapor compression refrigerator preferably includes at least one of the following components, for example.

[0007] That is, the constituent elements include a pressure sensor (S1) provided in a refrigerant passage of a vapor compression refrigerator to detect the pressure in the refrigerant passage, and a determination device (10) for determining whether a refrigerant leak has occurred, the determination device (10) receiving a detection signal from the pressure sensor (S1) and a signal indicating whether the compressor (2) is stopped, and the determination device (10) determines that a refrigerant leak has occurred when a value obtained by subtracting the detected pressure (Pi(n)) from the reference pressure (Pi(m)) is equal to or greater than a predetermined value.

[0008] The start-up date refers to the date on which the compressor (2) is started after being stopped for 24 hours or more. The reference pressure (Pi(m)) refers to the pressure detected by the pressure sensor (S1) when the compressor (2) is stopped on the start-up date. The detected pressure (Pi(n)) refers to the pressure detected by the pressure sensor (S1) when the compressor (2) has been stopped for more than 24 hours.

[0009] This allows the refrigerant leak detection device to detect a refrigerant leak even when the compressor (2) is stopped for a long period of time, and therefore, since a refrigerant leak can be detected early, it is possible to prevent a large amount of refrigerant from leaking out.

[0010] Incidentally, the symbols in each of the parentheses above are examples showing the correspondence with the specific configurations, etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations, etc. shown by the symbols in the parentheses above. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an air conditioner and the like according to a first embodiment. [Figure 2] The following "embodiments of the invention" are examples of embodiments that fall within the technical scope of the present disclosure. In other words, the invention-specific matters described in the claims are not limited to the specific configurations, structures, etc. shown in the following embodiments.

[0012] At least one of a component or part described with a reference numeral is provided unless otherwise specified, such as "one." The air conditioner described in this disclosure includes at least one of the components described with a reference numeral.

[0013] (First embodiment) <1. Overview of air conditioning equipment> In this embodiment, an example of a refrigerant leak detection device according to the present disclosure is applied to an air conditioning system for a server room. Heat-generating devices such as information and communication devices are installed in the server room. The air conditioning system cools the air in the server room (hereinafter abbreviated as the room) to maintain the air temperature in the room within a predetermined range.

[0014] An air conditioner uses cold energy generated by a vapor compression refrigerator to cool the air to be supplied to a room. Specifically, as shown in Fig. 1, the vapor compression refrigerator 1 is configured to include at least a compressor 2, a radiator 3, a pressure reducer 4, and an evaporator 5.

[0015] The compressor 2 compresses the gas phase refrigerant and discharges it to the radiator 3. The radiator 3 cools the high-pressure refrigerant. The pressure reducer 4 reduces the pressure of the high-pressure refrigerant that has flowed out from the radiator 3. The evaporator 5 exchanges heat between the reduced-pressure liquid phase refrigerant and the air to be supplied into the room, thereby cooling the air.

[0016] The air conditioner also includes a control unit 6 and a pressure sensor S1. The pressure sensor S1 detects the pressure in the refrigerant passage on the refrigerant outlet side of the evaporator 5. The control unit 6 controls the rotation speed of the compressor 2, the throttle opening of the pressure reducer 4, etc.

[0017] In addition, the control unit 6 in this embodiment controls the throttle opening of the pressure reducer 4 so that the degree of superheat of the refrigerant at the refrigerant outlet side of the evaporator 5 is within a predetermined range, and also controls the rotation speed of the compressor 2 according to the indoor temperature.

[0018] Therefore, the control unit 6 executes thermo-off control to stop the compressor 2 when the indoor temperature drops to a predetermined temperature (hereinafter referred to as the thermo-off temperature) and the rotation speed of the compressor 2 remains below a predetermined lower limit rotation speed for a predetermined period of time.

[0019] Then, after the thermo-off control is executed, when the indoor temperature reaches a predetermined temperature equal to or higher than the thermo-off temperature, the control unit 6 executes thermo-on control to restart the compressor 2. For this reason, in seasons such as winter when a large cooling capacity is not required, the compressor 2 stops for a long time.

[0020] 2. Refrigerant leak detection <2.1 Overview> In addition to the pressure detected by the pressure sensor S1, the control unit 6 also receives detected values ​​from a high-pressure side pressure sensor (not shown), a low-pressure refrigerant temperature sensor (not shown), an outside air temperature sensor (not shown), etc.

[0021] The control unit 6 then transmits the pressure detected by the pressure sensor S1 and the detected values ​​of the high-pressure side pressure sensors, etc., as well as a signal indicating the operating state of the compressor 2 to a determination device 10 in the integrated monitoring center. The determination device 10 uses the pressure detected by the pressure sensor S1 and the detected values ​​of the high-pressure side pressure sensors, etc., to remotely monitor the operating state of the air conditioning device, i.e., the vapor compression chiller 1.

[0022] Detection signals from sensors installed in one or more air conditioners are sent to the determination device 10. In other words, the one or more air conditioners are monitored in an integrated manner by the determination device 10.

[0023] The determination device 10 is configured by a computer having an arithmetic unit such as a CPU or a GPU, a ROM, a RAM, etc. The determination device 10 determines whether or not there is a refrigerant leak in an air conditioner according to software (including trained AI, etc.) pre-stored in a non-volatile storage unit such as a ROM.

[0024] <2.2 Refrigerant leak detection> <About vapor compression refrigeration units with operating compressors> In a vapor compression refrigerator (hereinafter referred to as a refrigerator) in which thermo-on control is being executed, the determination device 10 comprehensively determines whether a refrigerant leak has occurred by utilizing the detection values ​​of the pressure sensor S1, the high-pressure side pressure sensor, the low-pressure refrigerant temperature sensor, the outside air temperature sensor, etc.

[0025] That is, when the refrigerator operates without refrigerant leakage, the high pressure, low pressure, compressor rotation speed, etc. are balanced in accordance with the outdoor air temperature and the indoor air temperature. Then, the determination device 10 determines whether the balanced state is appropriate according to a predetermined algorithm.

[0026] <About vapor compression refrigerators with stopped compressors> In seasons such as winter when a large cooling capacity is not required, the compressor 2 may be stopped for a long time. As a result, the refrigerant pressures at various parts in the stopped refrigerator become approximately equal, making it impossible to detect a refrigerant leak using the above algorithm.

[0027] <Terminology> The start-up date refers to the date on which the compressor 2 starts up after being stopped for 24 hours or more. Specifically, if the compressor 2 has been stopped continuously during the winter (e.g., December to March) and is started up with the arrival of spring (e.g., April 1st), the start-up date is the date on which the compressor 2 first started up (in this case, April 1st).

[0028] The reference pressure Pi(m) is the pressure detected by the pressure sensor S1 when the compressor 2 is stopped on the start-up date. In other words, the reference date is the day when the compressor 2 is operating, and therefore the day when it is determined by the above algorithm that no refrigerant leakage has occurred.

[0029] Therefore, on a start-up day when no refrigerant leakage occurs, the pressure detected by the pressure sensor S1 when the compressor 2 is stopped can be considered to represent the pressure in the refrigerant passage when no refrigerant leakage occurs.

[0030] The detected pressure Pi(n) refers to the pressure detected by the pressure sensor S1 when the compressor 2 has been stopped for more than 24 hours. In other words, the detected pressure Pi(n) is the pressure detected when the compressor 2 is stopped continuously, such as during winter.

[0031] <Determination by determination device> The determination device 10 determines that a refrigerant leak has occurred when the value obtained by subtracting the detected pressure Pi(n) from the reference pressure Pi(m) is equal to or greater than a predetermined value. Note that the determination device 10 according to this embodiment makes the determination using the detected pressure Pi(n) acquired once a day at a predetermined time.

[0032] Specifically, when a refrigerant leak occurs and the compressor 2 is stopped for a long period of time, the detected pressure Pi(n) gradually decreases, as shown in Fig. 2. Then, the determination device 10 determines that a refrigerant leak has occurred when the value obtained by subtracting the detected pressure Pi(n) from the reference pressure Pi(m) is equal to or greater than a predetermined value.

[0033] 3. Features of the refrigerant leak detection device according to this embodiment As described above, the refrigerant leak detection device according to this embodiment is capable of detecting a refrigerant leak even when the compressor 2 is stopped for a long period of time. Therefore, since a refrigerant leak can be detected early, it is possible to prevent a large amount of refrigerant from leaking out.

[0034] (Other embodiments) The determination device 10 according to the above embodiment makes a determination using the detected pressure acquired once a day at a predetermined time. However, the present disclosure is not limited to this. That is, the present disclosure may acquire the detected pressure, for example, two or more times a day.

[0035] In the above-described embodiment, a detection value of a pressure sensor that detects the pressure in a low-pressure refrigerant passage of a vapor compression refrigerator is used. However, the present disclosure is not limited to this. That is, the present disclosure may also use, for example, a detection value of a pressure sensor that detects the pressure in a high-pressure refrigerant passage of a vapor compression refrigerator.

[0036] In the above-described embodiment, the determination device 10 is provided in the integrated monitoring center. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that the determination device 10 is provided in the control unit 6, for example.

[0037] Furthermore, the present disclosure is not limited to the above-described embodiments as long as it conforms to the spirit of the disclosure described in the above-described embodiments. Therefore, the present disclosure may be a configuration in which at least two of the above-described embodiments are combined, or a configuration in which any of the components illustrated or described with reference numerals in the above-described embodiments is eliminated. [Explanation of symbols]

[0038] 1. Vapor compression refrigerator 2... Compressor 3… Heatsink 4... Pressure reducer 5... Evaporator

Claims

1. A refrigerant leak detection device for detecting whether a refrigerant circulating in a vapor compression refrigerator is leaking from the vapor compression refrigerator, a pressure sensor provided in a refrigerant passage of the vapor compression refrigerator to detect a pressure in the refrigerant passage; a determination device for determining whether a refrigerant leak has occurred, to which a detection signal from the pressure sensor and a signal indicating whether the compressor has stopped are input; The day on which the compressor is started after being stopped for 24 hours or more is defined as the start-up day, and the pressure detected by the pressure sensor when the compressor is stopped on the start-up day is defined as the reference pressure. When the compressor has been stopped for more than 24 hours, the pressure detected by the pressure sensor during the stop state is set as the detected pressure. The determination device determines that a refrigerant leak has occurred when a value obtained by subtracting the detected pressure from the reference pressure is equal to or greater than a predetermined value.

2. The refrigerant leak detection device according to claim 1 , wherein the determination device makes the determination using the detected pressure obtained once a day at a predetermined time.

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