Refrigeration device and air conditioning device

Abstract

A refrigeration device provided with a refrigerant circuit through which a refrigerant circulates, wherein the refrigerant contains R32, a fluorescent agent for detecting refrigerant leakage from the refrigerant circuit is sealed inside the refrigerant circuit, and the fluorescent agent concentration, which is the concentration of the fluorescent agent contained in a mixture of refrigeration oil flowing through the refrigerant circuit and the fluorescent agent sealed in the refrigerant circuit, is less than or equal to 0.41 wt%.

Description

Refrigeration equipment and air conditioning equipment

[0001] The present disclosure relates to a refrigeration apparatus and an air conditioner in which a leak detection agent for detecting refrigerant leaks from a refrigerant circuit circulates through the refrigerant circuit together with the refrigerant.

[0002] A conventional example of this type of refrigeration system is the refrigeration system disclosed in Patent Document 1. In the refrigeration system disclosed in Patent Document 1, a fluorescent agent as a leak detection agent is circulated through the refrigerant circuit together with the refrigerant, and when inspecting for refrigerant leaks, ultraviolet light is irradiated from an ultraviolet lamp to check for the presence or absence of areas emitting light from the fluorescent agent, thereby making it possible to identify the location of the refrigerant leak.

[0003] International Publication No. 2018 / 225263

[0004] When a fluorescent agent is sealed in a refrigerant circuit, it circulates in the refrigerant circuit dissolved in the refrigerating machine oil. If more fluorescent agent than necessary is sealed in the refrigerant circuit and the concentration of fluorescent agent relative to the refrigerating machine oil (hereinafter referred to as the fluorescent agent concentration) is too high in relation to the type of refrigerant, the fluorescent agent will not dissolve in the refrigerating machine oil and will precipitate.

[0005] If the fluorescent agent precipitates, the precipitated solid or semi-solid such as sludge may clog components such as strainers provided in the refrigerant circuit, causing the refrigeration device to malfunction.

[0006] Although Patent Document 1 describes using a fluorescent agent to identify the location of a refrigerant leak, it does not describe the concentration of the fluorescent agent, and does not consider at all the issue of precipitation of the fluorescent agent.

[0007] The present disclosure has been made in consideration of these points, and provides a refrigeration apparatus and an air conditioner that can suppress deposition of a fluorescent agent and provide a highly reliable refrigeration apparatus.

[0008] The refrigeration device according to the present disclosure is a refrigeration device equipped with a refrigerant circuit through which a refrigerant circulates, the refrigerant containing R32, a fluorescent agent sealed inside the refrigerant circuit for detecting refrigerant leakage from the refrigerant circuit, and a fluorescent agent concentration, which is the concentration of the fluorescent agent contained in a mixture of refrigeration oil flowing through the refrigerant circuit and the fluorescent agent sealed in the refrigerant circuit, is 0.41 wt% or less.

[0009] The air conditioning apparatus according to the present disclosure includes the above-described refrigeration device, wherein the refrigerant circuit has a condenser and an evaporator, and at least one of the condenser and the evaporator is a heat exchanger that exchanges heat between the refrigerant and air.

[0010] The refrigeration apparatus and air conditioning apparatus according to the present disclosure can suppress the deposition of fluorescent agents and can be made highly reliable.

[0011] It is a refrigerant circuit diagram of the air conditioner according to Embodiment 1. It is a refrigerant circuit diagram when the air conditioner according to Embodiment 1 is a remote condensing unit.

[0012] A refrigeration system according to an embodiment will be described below with reference to the drawings. In this embodiment, the refrigeration system will be described as an air conditioner that cools a room. In the following drawings, the same reference numerals denote the same or equivalent parts, and these are common throughout the embodiments described below. The configurations of the components shown throughout the specification are merely examples, and are not limited to the configurations described in the specification.

[0013] Embodiment 1. [Configuration of Air Conditioning Apparatus 100] Fig. 1 is a refrigerant circuit diagram of an air conditioning apparatus 100 pertaining to Embodiment 1. The air conditioning apparatus 100 includes an outdoor unit 200 and an indoor unit 300, and the outdoor unit 200 and the indoor unit 300 are connected by a liquid extension pipe 11 and a gas extension pipe 12.

[0014] The air conditioning apparatus 100 has a refrigerant circuit A. The refrigerant circuit A has a main circuit 10a, an injection circuit 10b branched from the main circuit 10a, and an oil circuit 10c connected to an oil reservoir 1a of a compressor 1 (described later) of the main circuit 10a.

[0015] The main circuit 10a includes at least a compressor 1, a condenser 3, a pressure reducing device 7, and an evaporator 8. In the example of FIG. 1 , the main circuit 10a further includes an oil separator 2, a liquid receiver 4, a subcooling heat exchanger 5, a dryer 6, a strainer 16, and an accumulator 9. The main circuit 10a is a circuit in which the compressor 1, the oil separator 2, the condenser 3, the liquid receiver 4, the subcooling heat exchanger 5, the dryer 6, the pressure reducing device 7, the evaporator 8, the strainer 16, and the accumulator 9 are connected in this order by refrigerant piping 10 including a liquid extension piping 11 and a gas extension piping 12, and the refrigerant circulates. In the air conditioning apparatus 100, the compressor 1, the oil separator 2, the condenser 3, the liquid receiver 4, the subcooling heat exchanger 5, and the dryer 6 are arranged in the outdoor unit 200, and the pressure reducing device 7 and the evaporator 8 are arranged in the indoor unit 300.

[0016] The compressor 1 draws in refrigerant and compresses it to a high-temperature, high-pressure state. The oil separator 2 separates oil contained in the refrigerant discharged from the compressor 1 from the refrigerant. The condenser 3 is a heat exchanger that exchanges heat between the refrigerant and air. The condenser 3 cools and condenses the refrigerant discharged from the compressor 1. The receiver 4 is a container that stores excess refrigerant that has been liquefied in the refrigerant circuit A. The subcooling heat exchanger 5 has a high-pressure side flow path through which high-pressure refrigerant flows and a low-pressure side flow path through which low-pressure refrigerant flows, and performs heat exchange between the high-pressure refrigerant and the low-pressure refrigerant.

[0017] The dryer 6 removes foreign matter contained in the refrigerant. Foreign matter includes impurities and moisture. The pressure reducing device 7 reduces the pressure of the refrigerant to expand it. The pressure reducing device 7 is, for example, composed of an electronic expansion valve or a thermostatic expansion valve whose opening can be adjusted. The evaporator 8 is a heat exchanger that exchanges heat between the refrigerant and air. The evaporator 8 heats and evaporates the refrigerant that flows out from the pressure reducing device 7. The strainer 16 is provided on the suction side of the compressor 1 and captures foreign matter that has become mixed in the refrigerant. The accumulator 9 stores excess refrigerant.

[0018] The injection circuit 10b is a circuit that allows refrigerant between the subcooling heat exchanger 5 and the dryer 6 of the main circuit 10a to bypass the evaporator 8 and flow into the suction side of the compressor 1. The injection circuit 10b has an injection pipe 5b that branches off between the subcooling heat exchanger 5 and the dryer 6 and is connected to the suction side of the compressor 1 via a low-pressure side flow path of the subcooling heat exchanger 5. The injection circuit 10b has a pressure reducing device 5a that is provided in the injection pipe 5b upstream of the low-pressure side flow path of the subcooling heat exchanger 5 and is configured, for example, with an expansion valve.

[0019] The oil circuit 10c has an oil drain pipe 10c1. One end of the oil drain pipe 10c1 is connected to an oil supply / drain port 1b that communicates with an oil reservoir 1a provided at the bottom of the compressor 1, and the other end is connected to the accumulator 9. The oil supply / drain port 1b is provided through the container of the compressor 1 and is an opening for discharging oil from the inside of the container of the compressor 1 or for supplying oil to the inside of the container.

[0020] The refrigerant circuit A further includes a plurality of ports. The plurality of ports includes a suction port 13 provided upstream of the compressor 1, specifically, upstream of the accumulator 9, a discharge port 14 provided downstream of the compressor 1, and a compressor port 15 provided in the oil drain pipe 10c1. The plurality of ports also includes an oil concentration measurement port 18 provided upstream of the compressor 1 and upstream of the suction port 13.

[0021] The suction port 13 and the discharge port 14 are ports to which a vacuum pump is connected when vacuuming the air conditioning apparatus 100 during installation. The suction port 13 and the discharge port 14 are also generally referred to as service ports. The compressor port 15 is a port for draining oil accumulated in the oil reservoir 1a of the compressor 1. The compressor port 15 is also referred to as an oil drain plug. The compressor port 15 is provided on the oil drain pipe 10c1. In the illustrated example, a fluorescent agent sealing device 20 that seals a fluorescent agent as a leak detection agent inside the refrigerant circuit A is connected to the compressor port 15. Note that the fluorescent agent sealing device 20 is not limited to being connected to the compressor port 15 and may also be connected to the suction port 13 or the discharge port 14.

[0022] The oil concentration measurement port 18 is a port through which the refrigerant and refrigeration oil are extracted when measuring the oil concentration in the refrigerant circuit A. The oil concentration measurement port 18 is provided upstream of the strainer 16. The suction port 13 provided downstream of the strainer 16 may also be used as the oil concentration measurement port. In addition, the refrigerant circuit A is provided with a ball valve 17 between the suction port 13 and the strainer 16, which is opened and closed when, for example, refrigeration oil is injected into the refrigerant circuit A.

[0023] A capsule fluorescent agent having a container filled with a fluorescent agent is used in fluorescent agent inclusion device 20. Note that fluorescent agent inclusion device 20 is not limited to a capsule fluorescent agent, and any device that has a fluorescent agent and can inject the fluorescent agent into refrigerant circuit A may be used.

[0024] Next, the flow of refrigerant in the main circuit 10a and the injection circuit 10b of the refrigerant circuit A will be described.

[0025] The high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows into the condenser 3 after the oil contained in the refrigerant is separated in the oil separator 2. The high-temperature, high-pressure gas refrigerant that has flowed into the condenser 3 exchanges heat with the outdoor air in the condenser 3 and condenses to become a high-pressure liquid refrigerant or a two-phase refrigerant, which is stored in the receiver 4. The refrigerant that flows out of the receiver 4 flows into the high-pressure side flow path of the subcooling heat exchanger 5 and exchanges heat with the refrigerant passing through the low-pressure side flow path of the subcooling heat exchanger 5, thereby becoming a subcooled high-pressure liquid refrigerant.

[0026] The high-pressure liquid refrigerant that flows out from the subcooling heat exchanger 5 flows into the dryer 6, where foreign matter is removed. Foreign matter includes impurities and moisture. The liquid refrigerant that flows out from the dryer 6 is decompressed by the pressure reducing device 7 of the indoor unit 300 to become a low-temperature, low-pressure two-phase refrigerant, and flows into the evaporator 8. The refrigerant that flows into the evaporator 8 exchanges heat with the indoor air and evaporates. At this time, the indoor air is cooled by the refrigerant, cooling the room. The refrigerant that has evaporated in the evaporator 8 becomes a low-temperature, low-pressure gas refrigerant and returns to the compressor 1 via the accumulator 9.

[0027] A portion of the refrigerant flowing out from the high-pressure side of the subcooling heat exchanger 5 flows into the injection circuit 10b. The refrigerant flowing into the injection circuit 10b is decompressed by the pressure reducing device 5a, flows into the low-pressure side flow path of the subcooling heat exchanger 5, exchanges heat with the refrigerant flowing in the high-pressure side flow path of the subcooling heat exchanger 5, and is then injected into the compressor 1.

[0028] The configuration of the refrigerant circuit A is not limited to the configuration shown in Fig. 1. For example, the refrigerant circuit A may have a four-way valve or the like that switches the refrigerant flow path, allowing switching between cooling operation and heating operation. The refrigerant circuit A may also be configured exclusively for heating. When the refrigerant circuit A is configured exclusively for heating, the heat exchanger installed in the outdoor unit 200 functions as an evaporator, and the heat exchanger installed in the indoor unit 300 functions as a condenser. In other words, the refrigerant circuit A may be configured to include at least the compressor 1, the condenser 3, the pressure reducing device 7, and the evaporator 8.

[0029] Furthermore, the air conditioning apparatus 100 is not limited to the air-cooled air conditioning apparatus described above, but may also be a water-cooled air conditioning apparatus. Therefore, the air conditioning apparatus 100 may be configured such that at least one of the condenser 3 and the evaporator 8 is a heat exchanger that exchanges heat between the refrigerant and the air.

[0030] Furthermore, in this embodiment 1, the air conditioning device 100 is configured such that one indoor unit 300 is connected to one outdoor unit 200, but this is not limited to this, and the air conditioning device 100 may be configured such that any number of indoor units 300 are connected to one outdoor unit 200.

[0031] The air conditioning device 100 can also be a remote condensing unit as shown in the following FIG.

[0032] Fig. 2 is a refrigerant circuit diagram when the air conditioning apparatus 100 according to Embodiment 1 is a remote condensing unit. The remote condensing unit has a configuration in which the components provided in the outdoor unit 200 in Fig. 1 except for the condenser 3 are installed in a compression unit 201 located indoors, and the condenser 3 is installed in the outdoor unit 200A.

[0033] For example, the air conditioning device 100 can also be an air conditioning device that has each device that makes up the refrigerant circuit A and other auxiliary devices within a single unit, such as a cooling unit, and that is connected by refrigerant piping 10.

[0034] The air conditioning apparatus 100 configured as described above uses the fluorescent agent injecting device 20 to inject a fluorescent agent into the refrigerant circuit A. The air conditioning apparatus 100 then drives the compressor 1, which serves as the driving source for refrigerant circulation, to circulate the fluorescent agent together with the refrigerant through the refrigerant circuit A, and can detect refrigerant leaks by identifying the location from which the fluorescent agent has leaked.

[0035] The fluorescent agent used is a fluorescent agent that emits light when exposed to ultraviolet or visible light emitted from an ultraviolet lamp. For example, a fluorescent dye such as that described in JP 2018-184588 A is used as the fluorescent agent. An inspector scans the suspected refrigerant leak area with the ultraviolet or visible light from the ultraviolet lamp, and identifies the refrigerant leak location by checking the emission of the fluorescent agent.

[0036] When the fluorescent agent is sealed in the refrigerant circuit A, it dissolves in the refrigerant oil circulating inside the refrigerant circuit A together with the refrigerant. The fluorescent agent dissolves in the refrigerant oil but is less soluble in the refrigerant. If the concentration of the fluorescent agent sealed in the refrigerant circuit is higher than necessary, the fluorescent agent may not completely dissolve and precipitate depending on the type of refrigerant. Whether the fluorescent agent precipitates is also affected by the temperature and oil concentration of the refrigerant oil. The fluorescent agent has the property of precipitating and solidifying at low temperatures. The location where the fluorescent agent is likely to precipitate is the low-pressure section. The low-pressure section is, for example, the low-pressure section inside the compressor 1 or the accumulator 9. Furthermore, the precipitation of the fluorescent agent is particularly affected by the oil concentration in the suction pipe, including the strainer 16.

[0037] Even if the oil concentration changes, the concentrations of the fluorescent agent and refrigeration oil remain constant. However, as the oil concentration and the temperatures of the refrigerant and refrigeration oil decrease, the amount of fluorescent agent that can dissolve in the refrigeration oil decreases, making the fluorescent agent more likely to precipitate. Therefore, if the oil concentration decreases due to an increase in liquid refrigerant caused by liquid backflow, the fluorescent agent that is no longer completely dissolved in the refrigeration oil is more likely to precipitate. If the precipitated fluorescent agent flows through the refrigerant circuit in a solid or semi-solid state, it can clog components such as the strainer 16 installed in the refrigerant circuit, preventing the refrigerant from returning to the compressor and causing abnormal discharge temperatures, leading to an abnormal shutdown of the air conditioner or compressor failure due to poor refrigeration oil return. Thus, precipitation in the refrigerant circuit can cause the air conditioner to malfunction.

[0038] In light of this, the present inventors have discovered a concentration of the fluorescent agent that can suppress deposition of the fluorescent agent within the operating range of the air conditioning apparatus 100.

[0039] Here, as described above, the fluorescent agent may be a fluorescent dye such as that described in JP 2018-184588 A. The refrigerant circulating through the refrigerant circuit A may be a high density refrigerant such as R410A, R463A-J, R454B, R454C, or R32 simple refrigerant.

[0040] [Examples] Examples will be described below, but the present disclosure is not limited to the following examples.

[0041] Below, we will explain the results of a precipitation test to check for the presence or absence of precipitation of the fluorescent agent. In the precipitation test, the fluorescent agent concentration was set to an integer multiple (1x, 2x, ...) of the initial fluorescent agent concentration at the time of shipment, and the temperature and oil concentration of the air conditioner 100 were changed at each fluorescent agent concentration, and the presence or absence of precipitation was checked. When the fluorescent agent precipitates, it becomes cloudy, so the presence or absence of precipitation can be confirmed visually. The temperature range was -65°C to 25°C, and the oil concentration range was 1% to 100%, and the precipitation test was conducted over a wide operating range of the air conditioner 100, including both within and outside the operating range of temperature and oil concentration.

[0042] Because the oil concentration changes during operation, it is necessary to ensure that no precipitation occurs at any oil concentration within the operating range. The oil concentration is 75% or higher during normal operation, but it can be reduced to 1% by experimentally causing liquid backflow or adjusting the amount of refrigeration oil, making it possible to obtain the data in the table below. The oil concentration can be obtained by extracting refrigerant and refrigeration oil from the suction port 13 or an oil concentration measurement port 18 provided in the refrigerant circuit, particularly near the suction pipe of the compressor 1, and measuring the ratio between them.

[0043] Here, the fluorescent agent concentration is the concentration of the fluorescent agent contained in the mixture of the refrigerating machine oil flowing through refrigerant circuit A and the fluorescent agent sealed in refrigerant circuit A, and can be defined by the following calculation formula. The fluorescent agent concentration can be analyzed, for example, by gas chromatography analysis. Fluorescent agent concentration [wt %] = mass of fluorescent agent [g] ÷ (mass of refrigerating machine oil [g] of air conditioner 100 + mass of fluorescent agent [g]) × 100

[0044] The oil concentration can be defined by the following calculation formula: Oil concentration [wt %] = Mass [g] of refrigeration oil in air conditioning device 100 ÷ (Mass [g] of refrigeration oil in air conditioning device 100 + Mass [g] of refrigerant in air conditioning device 100) × 100

[0045] The initial fluorescent agent concentration is the concentration of the fluorescent agent sealed in the air conditioning apparatus 100 when the air conditioning apparatus 100 is installed on-site. The air conditioning apparatus 100 is shipped with a capsule fluorescent agent included. Therefore, the initial fluorescent agent concentration is a concentration determined from the mass of the fluorescent agent filled in the capsule fluorescent agent and the mass of the refrigeration oil sealed in the air conditioning apparatus 100, and is 0.0082 wt% in this embodiment. Note that the air conditioning apparatus 100 may have a fluorescent agent sealed in the product at the time of shipment, in which case the initial fluorescent agent concentration is determined using the mass of the sealed fluorescent agent.

[0046] The temperature of the air conditioner 100 is the temperature of the refrigerant and refrigerating machine oil.

[0047] The results of the precipitation test are shown in the table below. Here, we will explain how to read the table. In the table, ○ indicates no precipitation, and × indicates precipitation. The precipitation test shows the results under conditions combining temperatures of 25°C, -15°C, -35°C, -45°C, and -65°C with oil concentrations of 1%, 10%, 20%, 50%, 75%, and 100%. Note that the conditions for each cell in each table below, for example, the conditions for a cell with a temperature of -15°C and an oil concentration of 10% refer to temperatures of -15°C or lower, above -35°C, and oil concentrations of more than 1% and 10% or lower. The other cells can be read in a similar manner.

[0048] In addition, in each table, cells without dotted hatching indicate results within the normal operating range of the air conditioner 100.

[0049] Cells hatched with dark dots represent results outside the operating range, specifically, the results for the combination of an oil temperature of either 1% or 10% and a temperature of -65°C.

[0050] That is, cells not hatched with dots indicate results within the operating range of the air conditioning device 100, and cells hatched with dark dots indicate results outside the operating range of the air conditioning device 100.

[0051] Note that the cells hatched with thin dots show the results in a so-called liquid back state, where liquid refrigerant returns to the compressor. Because operation is possible in a liquid back state, the following table classifies the state as within the operating range in terms of oil concentration. However, the liquid back state cannot be considered a normal operating state, and is outside the normal operating range.

[0052] Example 1 A precipitation test was conducted using R410A as the refrigerant and Daphne Hermetic Oil (registered trademark) FVC32EA (ether oil) as the refrigeration oil. The precipitation test was conducted by setting the fluorescent agent concentration to 1, 2, 10, 50, and 100 times the initial fluorescent agent concentration at the time of shipment, and changing the temperature and oil concentration of the air conditioner 100 at each fluorescent agent concentration to observe whether precipitation occurred.

[0053] Therefore, the precipitation test was performed with the fluorescent agent concentration set to 0.0082 wt% (measured value), which is 1 times the initial fluorescent agent concentration, 0.0164 wt% (measured value), which is 2 times the initial fluorescent agent concentration, and 0.082 wt% (measured value), which is 10 times the initial fluorescent agent concentration.The precipitation test was also performed with the fluorescent agent concentration set to 0.41 wt% (predicted value), which is 50 times the initial fluorescent agent concentration, and 0.82 wt% (predicted value), which is 100 times the initial fluorescent agent concentration.

[0054] Table 1 shows the results when the fluorescent agent concentration was 0.0082 wt %.

[0055]

[0056] From Table 1, when the fluorescent agent concentration was 0.0082 wt %, no precipitation was observed under any of the conditions.

[0057] Table 2 shows the results when the fluorescent agent concentration was 0.0164 wt %.

[0058]

[0059] From Table 2, it can be seen that when the fluorescent agent concentration is 0.0164 wt%, precipitation occurs at temperatures below -65°C and oil concentrations below 1%. However, these conditions are outside the operating range, and the air conditioning device 100 will not operate under these conditions. Therefore, it can be said that precipitation of the fluorescent agent can be suppressed if the fluorescent agent concentration is 0.0164 wt% or less.

[0060] Table 3 shows the results when the fluorescent agent concentration was 0.082 wt %.

[0061]

[0062] From Table 3, it can be seen that when the fluorescent agent concentration is 0.082 wt%, precipitation occurs at temperatures below -45°C and oil concentrations below 10%. However, these conditions are outside the operating range, and the air conditioning device 100 will not operate under these conditions. Therefore, it can be said that precipitation of the fluorescent agent can be suppressed if the fluorescent agent concentration is 0.082 wt% or less.

[0063] Table 4 shows the results when the fluorescent agent concentration was 0.41 wt %.

[0064]

[0065] Table 4 shows that when the fluorescent agent concentration was 0.41 wt%, precipitation occurred at temperatures below -35°C and oil concentrations below 20%. While an oil concentration of 20% is within the operating range, it is an abnormal operating state (liquid backflow) and is not a normal operating state. In actual equipment, if the oil concentration remains below 20% for a sustained period, the compressor's reliability cannot be guaranteed, so the compressor is equipped with a control that performs an abnormal shutdown, making the risk of precipitation low. Furthermore, even if precipitation does occur, once the refrigerant temperature and oil concentration recover and increase, the precipitates will disappear and the compressor will be able to operate again, so precipitation at an oil concentration of 20% is within the acceptable range. In other words, fluorescent agent concentrations of 0.41 wt% or less are within the acceptable range.

[0066] Table 5 shows the results when the fluorescent agent concentration was 0.82 wt %.

[0067]

[0068] Table 5 shows that when the fluorescent agent concentration is 0.82 wt%, precipitation occurs when the temperature is below -15°C and the oil concentration is below 50%. This condition is included in the operating range. Therefore, since precipitation may occur during operation of the air conditioning device 100, a fluorescent agent concentration of 0.82 wt% cannot be used.

[0069] From the above, when using R410A as the refrigerant, the upper limit of the fluorescent agent concentration that can suppress precipitation within the operating range is 0.41 wt%. If it is desired to suppress not only precipitation within the operating range but also precipitation during operating conditions that cause liquid backflow, the upper limit of the fluorescent agent concentration can be reduced to 0.082 wt%.

[0070] Example 2 A precipitation test was conducted using R463A-J as the refrigerant and Daphne Hermetic Oil (registered trademark) FVC32EA (ether oil) as the refrigeration oil. The precipitation test was conducted by setting the fluorescent agent concentration to 1, 2, and 10 times the initial fluorescent agent concentration at the time of shipment, and observing the presence or absence of precipitation while changing the temperature of the air conditioner 100 from -65°C to 25°C and the oil concentration from 1% to 100% at each fluorescent agent concentration.

[0071] Therefore, the precipitation test was performed with the fluorescent agent concentration set to 0.0082 wt% (measured value), which is one time the initial fluorescent agent concentration, 0.0164 wt% (measured value), which is two times the initial fluorescent agent concentration, and 0.082 wt% (measured value), which is ten times the initial fluorescent agent concentration.

[0072] Table 6 shows the results when the fluorescent agent concentration was 0.0082 wt %.

[0073]

[0074] From Table 6, when the fluorescent agent concentration was 0.0082 wt %, no precipitation was observed under any of the conditions.

[0075] Table 7 shows the results when the fluorescent agent concentration was 0.0164 wt %.

[0076]

[0077] From Table 7, when the fluorescent agent concentration was 0.0164 wt %, no precipitation was observed under any of the conditions.

[0078] Based on the above, when using R463A-J as the refrigerant, the upper limit of the fluorescent agent concentration that can suppress precipitation within the operating range is 0.0164 wt%. Although precipitation testing has not been conducted, it is predicted that the upper limit of the fluorescent agent concentration can be extended to 0.41 wt% when using R463A-J as the refrigerant, similar to R410A, for the following reasons. In Table 2 of the R410A test results, precipitation occurred (×) at a fluorescent agent concentration of 0.0164 wt%, a temperature of -65°C, and an oil concentration of 1%. On the other hand, in Table 7 of the R463A-J test results, precipitation did not occur (○) at a fluorescent agent concentration of 0.0164 wt%, a temperature of -65°C, and an oil concentration of 1%. In other words, precipitation is less likely to occur with R463A-J than with R410A. Therefore, even in the case of R463A-J, if the upper limit of the fluorescent agent concentration is 0.41 wt % or less, the possibility of precipitation is small.

[0079] Similarly, even when using R454B, R454C, or R32 as the refrigerant alone, the upper limit of the fluorescent agent concentration at which deposition can be suppressed is predicted to be 0.41 wt%. Furthermore, although the refrigeration oil used in the deposition test was ether oil, it is predicted that similar results would be obtained even if other refrigeration oils, such as ester oil, were used.

[0080] Here, the R410A, R463A-J, R454B, R454C and R32 single refrigerants used as refrigerants have in common that they contain R32. Specifically, R410A, R463A-J and R454B are mixed refrigerants containing 20% ​​or more of R32, as follows: R410A: R32 = 50%, R125 = 50% R463A-J: R32 = 36%, R125 = 30%, R134a = 14%, R1234yf = 14%, R744 (CO ２ )=6% ●R454B: R32=68.9%, R1234yf=31.1% ●R454C: R32=21.5%, R1234yf=78.5%

[0081] Therefore, when a refrigerant containing R32, particularly a mixed refrigerant containing 20% ​​or more of R32 or a simple R32 refrigerant, is used, it can be said that precipitation of the fluorescent agent can be suppressed if the upper limit of the fluorescent agent concentration is 0.41 wt% or less.

[0082] As mentioned above, the upper limit of the fluorescent agent concentration, 0.41 wt%, corresponds to 50 times the initial fluorescent agent concentration. When the fluorescent agent is filled into the refrigerant circuit A of the air conditioning unit 100, the filling process is performed on-site by an installation technician using, for example, capsule fluorescent agent. While the possibility of excessive fluorescent agent being filled during the filling process cannot be denied, in practice, when capsule fluorescent agent is used, it is unlikely that the fluorescent agent will be filled to a concentration 50 times the initial fluorescent agent concentration. Therefore, by setting the upper limit of the fluorescent agent concentration in the refrigerant circuit A to 50 times the initial fluorescent agent concentration, the air conditioning unit 100 can effectively suppress precipitation.

[0083] In the air conditioning apparatus 100, if the concentration of the fluorescent agent in the refrigerant circuit A is too low, the fluorescent agent will not emit enough light, and the light will not be visible when a refrigerant leak occurs in the refrigerant circuit A. Therefore, the air conditioning apparatus 100 of embodiment 1 sets a lower limit for the fluorescent agent concentration so that the light can be visible when a refrigerant leak occurs in the refrigerant circuit A.

[0084] The lower limit of the fluorescent agent concentration is set to half the initial fluorescent agent concentration. Since the initial fluorescent agent concentration is 0.0082 wt% as described above, the lower limit of the fluorescent agent concentration is 0.0041 wt%. The concentration of half the initial fluorescent agent concentration was set in consideration of the need to ensure that the fluorescent agent can be illuminated with an ultraviolet lamp or visible light even if a small amount of capsule fluorescent agent spills when the capsule fluorescent agent is sealed into refrigerant circuit A on-site, or if a small amount spills together with the refrigerating machine oil when the refrigerating machine oil is changed.

[0085] As described above, if the fluorescent agent concentration is 0.41 wt% or less, the precipitation of the fluorescent agent during operation can be suppressed, making the air conditioning device 100 highly reliable. Also, if the fluorescent agent concentration is 0.0041 wt% or more, the air conditioning device 100 can make the fluorescent agent emit light using an ultraviolet lamp or visible light.

[0086] [Effects of the Air Conditioning Apparatus 100] The air conditioning apparatus 100 is equipped with a refrigerant circuit A through which a refrigerant circulates, the refrigerant being a refrigerant containing R32. A fluorescent agent is sealed inside the refrigerant circuit A to detect refrigerant leaks from the refrigerant circuit A. The fluorescent agent concentration, which is the concentration of the fluorescent agent contained in a mixture of the refrigeration oil flowing through the refrigerant circuit A and the fluorescent agent inside the refrigerant circuit A, is 0.41 wt % or less.

[0087] This makes it possible for the air conditioning apparatus 100 to suppress deposition of the fluorescent agent during operation, making it highly reliable.

[0088] A refrigerant containing R32 is a mixed refrigerant containing 20% ​​or more of R32 or a refrigerant containing R32 alone. A mixed refrigerant containing 20% ​​or more of R32 is specifically any of R410A, R463A-J, R454B, and R454C.

[0089] This makes it possible for the air conditioning apparatus 100 to suppress deposition of the fluorescent agent during operation, making it highly reliable.

[0090] Furthermore, if the fluorescent agent concentration is 0.082 wt % or less, the air conditioning apparatus 100 can suppress deposition of the fluorescent agent not only within the operating range but also in operating states in which liquid backflow occurs.

[0091] Furthermore, by setting the fluorescent agent concentration to 0.0041 wt % or more, an inspector can check the emission of the fluorescent agent in the air conditioning apparatus 100 using an ultraviolet lamp or visible light.

[0092] As the refrigerating machine oil, ether oil or ester oil can be used.

[0093] In the first embodiment, the refrigeration device is described as an air conditioner, but the refrigeration device may be a chiller for cooling a refrigerated warehouse or the like, or a water heater.

[0094] 1 Compressor, 1a Oil reservoir, 1b Oil supply / discharge port, 2 Oil separator, 3 Condenser, 4 Receiver, 5 Subcooling heat exchanger, 5a Pressure reducing device, 5b Injection piping, 6 Dryer, 7 Pressure reducing device, 8 Evaporator, 9 Accumulator, 10 Refrigerant piping, 10a Main circuit, 10b Injection circuit, 10c Oil circuit, 10c1 Oil drain pipe, 11 Liquid extension piping, 12 Gas extension piping, 13 Suction port, 14 Discharge port, 15 Compressor port, 16 Strainer, 17 Ball valve, 18 Oil concentration measurement port, 20 Fluorescent agent sealing device, 100 Air conditioning device, 200 Outdoor unit, 200A Outdoor unit, 201 Compression unit, 300 Indoor unit, A Refrigerant circuit.

Claims

1. A refrigeration system equipped with a refrigerant circuit through which a refrigerant circulates, the refrigerant containing R32, a fluorescent agent sealed inside the refrigerant circuit for detecting refrigerant leakage from the refrigerant circuit, and a fluorescent agent concentration, which is the concentration of the fluorescent agent contained in a mixture of refrigeration oil flowing through the refrigerant circuit and the fluorescent agent sealed in the refrigerant circuit, is 0.41 wt % or less.

2. The refrigeration system according to claim 1, wherein the refrigerant is a mixed refrigerant containing 20% ​​or more of R32 or a single refrigerant of R32.

3. A refrigeration system according to claim 2, wherein the mixed refrigerant is any one of R410A, R463A-J, R454B and R454C.

4. A refrigeration device as claimed in any one of claims 1 to 3, wherein the concentration of the fluorescent agent is 0.082 wt % or less.

5. A refrigeration system as claimed in any one of claims 1 to 4, wherein the concentration of the fluorescent agent is 0.0041 wt % or more.

6. A refrigeration system according to any one of claims 1 to 5, wherein the refrigeration oil is ether oil or ester oil.

7. A refrigeration device according to any one of claims 1 to 6, wherein the refrigerant circuit comprises a compressor that draws in and compresses the refrigerant, and a strainer provided on the suction side of the compressor.

8. An air-conditioning system comprising the refrigeration device according to any one of claims 1 to 7, wherein the refrigerant circuit has a condenser and an evaporator, and at least one of the condenser and the evaporator is a heat exchanger that exchanges heat between the refrigerant and air.

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