Freezer

Abstract

To provide a technology capable of easily repairing tiny gaps generated in a refrigerant circuit.SOLUTION: A freezer 1 has a refrigerant circuit 10. In the refrigerant circuit 10, a highly flammable refrigerant, an odorous component, and a refrigerant leakage prevention agent 100 are encapsulated. The refrigerant leakage prevention agent 100 repairs gaps that are generated in the refrigerant circuit 10 and have a diameter or hydraulic diameter of 30 μm or less. Consequently, the freezer 1 can easily repair tiny gaps that are generated in the refrigerant circuit 10 using the refrigerant leakage prevention agent 100 encapsulated in the refrigerant circuit 10.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to refrigeration devices. [Background technology]

[0002] Conventionally, refrigeration systems have been known in which a highly flammable refrigerant with a low global warming potential (GWP) is sealed in the refrigerant circuit. In this type of refrigeration system, it is important to quickly detect any refrigerant leakage from the refrigerant circuit and prevent the refrigerant from combusting.

[0003] Patent Document 1 discloses a refrigeration cycle device in which, in addition to the refrigerant, an odorous component, a sulfur-based odorant, is sealed in the refrigerant circuit. When the refrigerant leaks from the refrigerant circuit, the odorous component also leaks, allowing people nearby to recognize the abnormality and take the necessary measures. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7162786 Summary of the Invention [Problem to be solved by the invention]

[0005] However, minute gaps may develop in the pipes and other components that make up the refrigerant circuit due to deterioration over time. It is desirable to configure the system to automatically repair such minute gaps rather than letting odorous components leak and alerting people nearby to an abnormality.

[0006] The present disclosure provides a technique that can easily repair minute gaps that occur in a refrigerant circuit. [Means for solving the problem]

[0007] One aspect of the present disclosure is a refrigeration device having a refrigerant circuit, in which a highly flammable refrigerant, an odorous component, and a refrigerant leakage prevention agent are sealed, and the refrigerant leakage prevention agent repairs gaps that occur in the refrigerant circuit and have a diameter or hydraulic diameter of 30 μm or less.

[0008] According to the above, the refrigeration device can easily repair small gaps that occur in the refrigerant circuit using a refrigerant leakage prevention agent. That is, the refrigeration device automatically fills gaps in the refrigerant circuit that are 30 μm or smaller with the refrigerant leakage prevention agent to prevent the leakage of odorous components. On the other hand, if a large amount of refrigerant leaks through a gap that is larger than 30 μm, the refrigeration device can make nearby people aware of the refrigerant leak by using odorous components. In other words, by combining the odorous components and the refrigerant leakage prevention agent, the refrigeration device can selectively repair the refrigerant circuit or alert nearby people.

[0009] The refrigerant circuit may include a heat exchanger, and the gap may be a hole formed in a heat transfer tube of the heat exchanger.

[0010] This allows the refrigeration device to easily close gaps that occur in the heat transfer tubes with the refrigerant leakage prevention agent.

[0011] The refrigerant circuit has at least two pipes and a flare connection portion that connects the at least two pipes, and the gap is formed in the flare connection portion.

[0012] This allows the refrigeration apparatus to easily seal any gaps that occur in the flare connection portion with the refrigerant leakage prevention agent.

[0013] The refrigerant leakage prevention agent is organic or inorganic fine particles that aggregate and fill the gaps.

[0014] The organic or inorganic particles allow the refrigeration device to create a suspension in the gaps, thereby blocking the gaps.

[0015] The organic or inorganic fine particles include a fluorine-containing resin or a silicon-containing resin.

[0016] This allows the refrigeration device to continuously maintain the properties of the refrigerant leakage prevention agent filled in the refrigerant circuit, and to smoothly aggregate the agent if any gaps occur.

[0017] The refrigerant leakage prevention agent is a compound that reacts with moisture to form a sealant.

[0018] This allows the refrigerant leakage prevention agent to form a sealant with the moisture inside the gap, thereby sealing the gap.

[0019] The refrigerant leakage prevention agent is a compound containing a polymer monomer that undergoes a polymerization reaction to form a sealant.

[0020] In this case, too, the refrigerant leakage prevention agent can form a sealant inside the gap, thereby sealing the gap.

[0021] The refrigerant is a refrigerant containing a hydrocarbon as a main component.

[0022] This makes it possible to avoid environmental pollution even if the refrigerant is released into the atmosphere from the refrigerant circuit.

[0023] The odorous components are compounds containing sulfur.

[0024] This allows people in the vicinity to easily become aware of any leakage of refrigerant or odorous components from the refrigerant circuit.

[0025] The odor components include any one of tetrahydrothiophene, dimethyl sulfide, and ethyl methyl sulfide, or one or more of these as components.

[0026] As a result, the odorous components have superior odor quality and odor threshold compared to other sulfide-based components, and because they are chemically stabilized, the composition of the odorous components can be well maintained in the refrigerant circuit. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a diagram illustrating a schematic configuration of an air conditioning apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing heat transfer tubes and fins of an outdoor heat exchanger. [Figure 3] 10 is a flowchart showing an installation method including filling with a refrigerant leakage prevention agent. [Figure 4] Fig. 4(A) is a cross-sectional view showing a heat transfer tube with a gap formed therein. Fig. 4(B) is a first cross-sectional view showing the action of the refrigerant leakage prevention agent. Fig. 4(C) is a second cross-sectional view showing the action of the refrigerant leakage prevention agent. Fig. 4(D) is a third cross-sectional view showing the action of the refrigerant leakage prevention agent. [Figure 5] Fig. 5(A) is a flowchart showing the operation when a first gap is formed in the refrigerant circuit, and Fig. 5(B) is a flowchart showing the operation when a second gap is formed in the refrigerant circuit. [Figure 6] Fig. 6(A) is a first cross-sectional view showing the effect of the refrigerant leakage prevention agent at the flare connection portion, and Fig. 6(B) is a second cross-sectional view showing the effect of the refrigerant leakage prevention agent at the flare connection portion. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and duplicate explanations may be omitted. In each drawing, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding of the invention.

[0029] <Configuration of refrigeration equipment> A refrigeration device 1 according to an embodiment of the present disclosure is an air conditioner that adjusts the temperature of air in an indoor space. Hereinafter, the refrigeration device 1 will also be referred to as the air conditioner 1. The air conditioner 1 is used for cooling and heating indoor spaces by operating a vapor compression refrigeration cycle. In cooling operation, the air conditioner 1 cools the air in the indoor space to adjust the temperature. In heating operation, the air conditioner 1 heats the air in the indoor space to adjust the temperature.

[0030] The air conditioner 1 includes a refrigerant circuit 10 containing a refrigerant, an outdoor unit 20 which is a heat source unit installed in an outdoor space, and an indoor unit 30 which is a utilization unit installed in an indoor space. The refrigerant circuit 10 performs cooling operation and heating operation by circulating the refrigerant between the outdoor unit 20 and the indoor unit 30. The air conditioner 1 according to this embodiment is a pair type in which one outdoor unit 20 and one indoor unit 30 are connected. However, the air conditioner 1 may also be configured in such a way that one outdoor unit 20 is connected to multiple indoor units 30, or in such a way that multiple outdoor units 20 are connected to one indoor unit 30.

[0031] The refrigerant circuit 10 includes a first connection pipe 11 and a second connection pipe 12 that connect the outdoor unit 20 and the indoor unit 30. The first connection pipe 11 and the second connection pipe 12 are one or more tubes that connect the indoor space and the outdoor space and allow the refrigerant to flow. The first connection pipe 11 is a gas pipe that allows the refrigerant in a gaseous state to flow. The second connection pipe 12 is a liquid pipe that allows the refrigerant in a liquid state to flow.

[0032] The refrigerant circuit 10 also has an outdoor path 13 connected to one end of the first connecting pipe 11 and one end of the second connecting pipe 12 inside the outdoor unit 20. The refrigerant circuit 10 also has an indoor path 14 connected to the other end of the first connecting pipe 11 and the other end of the second connecting pipe 12 inside the indoor unit 30. The refrigerant circuit 10 forms an endless circulation circuit by the first connecting pipe 11, the second connecting pipe, the outdoor path 13, and the indoor path 14.

[0033] <Outdoor unit> The outdoor unit 20 has an outdoor path 13 installed inside a housing 20a, and thereby constitutes part of the refrigerant circuit 10. The outdoor unit 20 includes a compressor 21, an outdoor heat exchanger 22, an expansion valve 23, a four-way switching valve 24, and an outdoor fan 25. The compressor 21, the outdoor heat exchanger 22, the expansion valve 23, and the four-way switching valve 24 are connected to the outdoor path 13 of the outdoor unit 20.

[0034] During refrigeration cycle operation, the compressor 21 compresses low-pressure refrigerant drawn in through the suction connection end 21i to a high pressure, and discharges the high-pressure refrigerant from the discharge connection end 21o. For example, the compressor 21 may be a rotary device in which a sealed compression element is rotationally driven by a compressor motor 21m to pressurize the refrigerant. The suction connection end 21i and the discharge connection end 21o of the compressor 21 are connected to a four-way switching valve 24 through the outdoor path 13.

[0035] During cooling operation, the outdoor heat exchanger 22 dissipates heat from the refrigerant by exchanging heat between the refrigerant flowing therethrough and the outdoor air in a refrigeration cycle. A fin-and-tube mechanism, for example, can be used as the outdoor heat exchanger 22. A gas connection end 22G of the outdoor heat exchanger 22 is connected to a four-way switching valve 24 through the outdoor path 13. A liquid connection end 22L of the outdoor heat exchanger 22 is connected to an expansion valve 23 through the outdoor path 13.

[0036] For example, as shown in FIG. 2, a fin-and-tube outdoor heat exchanger 22 includes a serpentine heat transfer tube 22t and a plurality of fins 22f that support the heat transfer tube 22t.

[0037] The heat transfer tube 22t has a refrigerant flow path 22a therein. The wall of the heat transfer tube 22t is preferably formed thin to promote heat exchange with the outside. The thickness of the wall of the heat transfer tube 22t is preferably set to, for example, about 0.5 mm to 3 mm. The heat transfer tube 22t is also preferably formed from a material with high thermal conductivity. Examples of materials for the heat transfer tube 22t include copper, copper alloy, aluminum, and aluminum alloy.

[0038] The multiple fins 22f are formed as rectangular flat plates extending in the vertical direction. In the outdoor heat exchanger 22, multiple heat transfer tubes 22t are inserted through the multiple fins 22f. The multiple fins 22f are provided, for example, at equal intervals along the axial direction of the straight tube. Each fin 22f connected to the outer circumferential surface of the straight tube promotes heat exchange between the refrigerant flowing through the heat transfer tube 22t and the outdoor air.

[0039] 1 , the outdoor fan 25 blows outdoor air to the outdoor heat exchanger 22. For example, a propeller fan having a motor and a propeller (not shown) can be used as the outdoor fan 25. During cooling operation, the heat transfer tubes 22t and fins 22f of the outdoor heat exchanger 22 exchange heat between the refrigerant in the flow path 22a and the air blown by the outdoor fan 25, thereby enhancing the cooling effect of the refrigerant.

[0040] The expansion valve 23 reduces the pressure of the refrigerant that has flowed in through the outdoor path 13 to a low temperature. An electronic valve or a temperature-sensitive valve that adjusts the opening of an internal flow path is used as this expansion valve 23. The expansion valve 23 may also be provided in the indoor unit 30.

[0041] The four-way switching valve 24 reverses the flow of refrigerant in the refrigerant circuit 10 to selectively perform cooling operation or heating operation. The four-way switching valve 24 can be switched between a first state shown by the solid lines in Fig. 1 and a second state shown by the dashed lines in Fig. 1.

[0042] Specifically, in the first state, the four-way switching valve 24 communicates the discharge connection end 21o of the compressor 21 with the gas connection end 22G of the outdoor heat exchanger 22, while also communicating the suction connection end 21i of the compressor 21 with the first connection pipe 11 outside the outdoor unit 20. In this first state, the compressor 21 is driven, causing refrigerant to flow from the first connection pipe 11 into the outdoor path 13 of the outdoor unit 20. The refrigerant is compressed to high pressure by the compressor 21 and moves to the outdoor heat exchanger 22 through the four-way switching valve 24. The refrigerant releases heat in the outdoor heat exchanger 22 and is further decompressed in the expansion valve 23, becoming a low-pressure, low-temperature liquid, which then moves to the second connection pipe 12. In other words, the air conditioner 1 can perform cooling operation by drawing in high-temperature refrigerant through the first connection pipe 11 and sending low-temperature refrigerant to the indoor unit 30 through the second connection pipe 12.

[0043] In the second state, the four-way switching valve 24 communicates the discharge connection end 21o of the compressor 21 with the first connecting pipe 11 outside the outdoor unit 20, and also communicates the suction connection end 21i of the compressor 21 with the gas connection end 22G of the outdoor heat exchanger 22. In this second state, the compressor 21 is driven, causing refrigerant to flow from the second connecting pipe 12 into the outdoor path 13 of the outdoor unit 20. The refrigerant moves through the expansion valve 23 to the outdoor heat exchanger 22, and then moves from the outdoor heat exchanger 22 to the compressor 21. The refrigerant is compressed in the compressor 21 to become a high-pressure, high-temperature gas, and moves through the four-way switching valve 24 to the first connecting pipe 11. In other words, the air conditioner 1 can perform heating operation by drawing in low-temperature refrigerant through the second connecting pipe 12 and sending high-temperature refrigerant to the indoor unit 30 through the first connecting pipe 11.

[0044] The outdoor path 13 of the outdoor unit 20 can be divided into a gas line 13G, which mainly circulates gasified refrigerant, and a liquid line 13L, which mainly circulates liquid refrigerant. The gas line 13G in the outdoor path 13 refers to the piping that connects the connection point with the first connecting pipe 11 to the compressor 21 and the gas connection end 22G of the outdoor heat exchanger 22. The liquid line 13L in the outdoor path 13 refers to the piping that connects the connection point with the second connecting pipe 12 to the expansion valve 23 and the liquid connection end 22L of the outdoor heat exchanger 22. The gas line 13G and the liquid line 13L are provided with multiple valves. For example, the multiple valves include a first shut-off valve 41 and a second shut-off valve 42.

[0045] A first shut-off valve 41 is provided in the gas line 13G from the connection point of the first connecting pipe 11 to the compressor 21. Specifically, the first shut-off valve 41 is installed at the connection point between the gas line 13G and the first connecting pipe 11. The first shut-off valve 41 opens and closes the flow path of the gas line 13G based on the operation of an operator.

[0046] A second shut-off valve 42 is provided in the liquid line 13L from the connection point of the second connecting pipe 12 to the expansion valve 23. Specifically, the second shut-off valve 42 is installed at the connection point of the liquid line 13L and the second connecting pipe 12. The second shut-off valve 42 opens and closes the flow path of the liquid line 13L based on the operation of an operator.

[0047] Furthermore, the first shut-off valve 41 has a gas service port 44. The second shut-off valve 42 has a liquid service port 45. The gas service port 44 is larger than the liquid service port 45. The gas service port 44 and the liquid service port 45 are used when filling the refrigerant circuit 10 of the air conditioner 1 with refrigerant, when discharging refrigerant from the outdoor unit 20, when measuring the pressure of the refrigerant in the refrigerant circuit 10, etc.

[0048] <Indoor unit> The indoor unit 30 has an indoor path 14 installed inside a housing 30a, and thereby constitutes a part of the refrigerant circuit 10. The indoor unit 30 is equipped with an indoor heat exchanger 31 and an indoor fan 32. The indoor path 14 of the indoor unit 30 is connected to the indoor heat exchanger 31.

[0049] During refrigeration cycle operation, the indoor heat exchanger 31 exchanges heat between the refrigerant flowing therethrough and the indoor air. As a result, the indoor heat exchanger 31 can absorb heat from the indoor air to cool it when the refrigerant is at a lower temperature than the indoor air, and can release heat to the indoor air to warm it when the refrigerant is at a higher temperature than the indoor air. For example, a fin-and-tube mechanism can be used for this indoor heat exchanger 31. A gas connection end 31G of the indoor heat exchanger 31 is connected to the first connecting pipe 11 through the indoor path 14. A liquid connection end 31L of the indoor heat exchanger 31 is connected to the second connecting pipe 12 through the indoor path 14.

[0050] The indoor fan 32 blows indoor air to the indoor heat exchanger 31. For example, a cross-flow fan having a motor and a cylindrical impeller (not shown) is used as the indoor fan 32. The indoor air transported by the indoor fan 32 passes through the indoor heat exchanger 31 and is blown from the indoor heat exchanger 31 into the indoor space.

[0051] The indoor unit 30 also has a power supply circuit connected to a commercial power source. The air conditioning apparatus 1 operates the indoor unit 30 based on the supply of power from the commercial power source, and also operates the outdoor unit 20 via a power line (not shown).

[0052] <Air conditioner control unit> The air conditioning apparatus 1 has a control unit 90 that controls the operation of each component. The control unit 90 is made up of a first control device 91, a second control device 92, and a remote controller 93. The remote controller 93 is a device that allows the user to operate various commands to the air conditioning apparatus 1, and may be a dedicated controller or a mobile terminal such as a smartphone or tablet.

[0053] Each of the first control device 91, the second control device 92, and the remote controller 93 is a computer (more specifically, an MCU: Micro Control Unit) having a processor, memory, an input / output interface, and a communication interface. The processor is one or a combination of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), a circuit made up of multiple discrete semiconductors, etc. The memory includes non-volatile memory and volatile memory. The memory stores programs that control various processes, and the processor controls various operations by reading and executing the programs stored in the memory.

[0054] The first control device 91 is provided in the outdoor unit 20 and controls each component of the outdoor unit 20. The second control device 92 is provided in the indoor unit 30 and controls each component of the indoor unit 30. The first control device 91 and the second control device 92 can send and receive information to and from each other via wired or wireless communication. The second control device 92 and the remote controller 93 can send and receive information to and from each other via wired or wireless communication. The control unit 90 selectively performs cooling operation or heating operation in response to an operation command from the remote controller 93 by the user.

[0055] <Refrigerant> The refrigerant to be filled in the refrigerant circuit 10 should preferably have a GWP value as small as possible and have a low environmental impact. Examples of this type of refrigerant material include those primarily composed of hydrocarbons with 1 to 4 carbon atoms, such as R-290 (propane), R-1270 (propylene), and R-600a (isobutane). These refrigerant materials are highly flammable refrigerants that are more flammable than hydrofluorocarbons. In this embodiment, a case where propane is used as the refrigerant will be described. Alternatively, the refrigerant may be methane (R50), ethane (R170), butane (R600), ammonia (R717), or the like.

[0056] <Odor components> As described above, the air conditioner 1 seals odorous components together with the refrigerant to alert people to leaks of highly flammable refrigerant from the refrigerant circuit 10. Examples of these odorous components include sulfur-based odorants, which are sulfur-based compounds. Examples of sulfur-based odorants include sulfide-based odorants such as tetrahydrothiophene (THT), dimethyl sulfide (DMS), and ethyl methyl sulfide, as well as sulfide-based odorants mixed with thiols, thioethers, or the like. In this embodiment, a case where tetrahydrothiophene is used as the odorous component will be described. Hereinafter, tetrahydrothiophene may also be referred to as THT.

[0057] <Refrigerating machine oil> Furthermore, the air conditioner 1 seals refrigerating machine oil in the refrigerant circuit 10 together with the refrigerant and odorous components. The refrigerating machine oil is stored mainly at the bottom of the compressor 21 in the refrigerant circuit 10, and can be circulated to the compression elements in the compressor 21 to maintain the lubrication of the sliding parts. Furthermore, a portion of the refrigerating machine oil circulates within the refrigerant circuit 10 together with the refrigerant and odorous components. In other words, the refrigerating machine oil is mixed with the refrigerant and odorous components and used as a working fluid for the refrigerating machine. The proportion of the refrigerating machine oil sealed in the total amount of working fluid for the refrigerating machine is preferably 5% by mass or more and 60% by mass or less, and more preferably 10% by mass or more and 50% by mass or less.

[0058] Examples of refrigerating machine oils include oxygen-containing synthetic oils (ester-based refrigerating machine oils, ether-based refrigerating machine oils, etc.), hydrocarbon-based refrigerating machine oils, etc. Among these, ester-based refrigerating machine oils and ether-based refrigerating machine oils are preferred from the viewpoint of compatibility with the refrigerant. One type of refrigerating machine oil may be used alone, or two or more types may be used in combination.

[0059] From the viewpoint of chemical stability, examples of ester-based refrigerating machine oils include, as base oil components, dibasic acid ester oils of dibasic acids and monohydric alcohols, polyol ester oils of polyols and fatty acids, complex ester oils of polyols, polybasic acids, and monohydric alcohols (or fatty acids), polyol carbonate ester oils, and the like.

[0060] Examples of ether-based refrigerating machine oils include polyvinyl ether oils and polyoxyalkylene oils. Examples of polyvinyl ether oils include polymers of vinyl ether monomers, copolymers of vinyl ether monomers with hydrocarbon monomers having an olefinic double bond, and copolymers of vinyl ether monomers with monomers having an olefinic double bond and a polyoxyalkylene chain. Examples of polyoxyalkylene oils include polyoxyalkylene compounds obtained by polymerizing alkylene oxides having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, etc.) using water or a hydroxyl group-containing compound as an initiator. For example, polyalkylene glycol oils (PAG oils) are available. Polyoxyalkylene oils may also be obtained by etherifying or esterifying the hydroxyl groups of polyoxyalkylene compounds. The oxyalkylene units in a single molecule may be the same, or two or more types of oxyalkylene units may be included. It is preferred that a single molecule contains at least an oxypropylene unit.

[0061] <Other additives> The refrigerating machine oil sealed in the refrigerant circuit 10 may contain one or more additives. Examples of the additives include acid scavengers, extreme pressure agents, antioxidants, antifoaming agents, oiliness agents, metal deactivators such as copper deactivators, antiwear agents, and compatibilizers.

[0062] <Refrigerant leak prevention agent> In the air conditioner 1 configured as described above, corrosion caused by aging and other factors can cause tiny gaps such as holes and cracks in the pipes that make up the refrigerant circuit 10. For example, the heat transfer pipes 22t of the outdoor heat exchanger 22 are prone to condensation due to cooling of the surrounding air, and this condensation can cause corrosion to progress along the thickness direction of the wall, potentially creating holes that connect the flow path 22a to the outside.

[0063] To prevent the refrigerant and odorous components from leaking to the outside due to the occurrence of such minute gaps in the piping, the air conditioner 1 according to this embodiment has a refrigerant leakage prevention agent sealed in the refrigerant circuit 10. In other words, the refrigerant circuit 10 is sealed with the refrigerant, odorous components, and refrigerating machine oil. This refrigerant leakage prevention agent will be described in detail below.

[0064] The refrigerant leakage prevention agent sealed in the refrigerant circuit 10 flows into any small gaps that may occur in the piping, blocking the gaps at least partially, and preferably completely. This refrigerant leakage prevention agent can be organic or inorganic fine particles. For example, resin particles made of a resin material can be used as organic fine particles. Because gaps that occur in the piping are not necessarily uniform, the refrigerant leakage prevention agent is preferably fine particles with a wide particle size distribution.

[0065] The particle size distribution of the fine particles of the refrigerant leakage prevention agent may be, for example, D50 of 2.0 μm to 10.0 μm and D90 / D10 of 4.0 to 14.0. Here, D10, D50, and D90 refer to the particle sizes at cumulative volume percentages of 10%, 50%, and 90%, respectively, in the volume-based particle size distribution. The particle size distribution of the fine particles of the refrigerant leakage prevention agent may also include a standard deviation of, for example, 3.0 μm to 8.0 μm. The standard deviation is calculated from the particle size distribution measured, for example, by a centrifugal sedimentation particle size distribution measuring device. The lower limit of this standard deviation is more preferably 3.5 μm, and particularly preferably 4.0 μm. The upper limit of this standard deviation is more preferably 7.5 μm.

[0066] Furthermore, the resin constituting the refrigerant leakage prevention agent is preferably flexible. This allows the refrigerant leakage prevention agent to easily enter gaps in piping that may cause refrigerant leakage, regardless of their shape. Specific examples of resins for the refrigerant leakage prevention agent include silicon-containing resins and fluorine-containing resins. Refrigerant leakage prevention agents made of silicon-containing resins, fluorine-containing resins, etc., have a high specific gravity, making them easily dispersed uniformly in refrigerating machine oil. They also have high heat resistance, durability, and lubricity, and are stable against refrigerants and refrigerating machine oil, making them suitable. For example, preferred fluorine-containing resins include polytetrafluoroethylene (PTFE) resin, tetrafluoroethylene / hexafluoropropylene copolymer (FEP) resin, and tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) resin. PTFE resin is particularly preferred for the refrigerant leakage prevention agent, and low-molecular-weight PTFE resin is even more preferred.

[0067] The low-molecular-weight PTFE resin preferably has a melt viscosity of 1 × 10 to 7 × 10 Pa·s at 380°C. Among such low-molecular-weight PTFE resins, those that are substantially free of perfluorocarboxylic acids and / or salts thereof having 8 to 14 carbon atoms are preferred, and those that are substantially free of perfluorocarboxylic acids having 8 carbon atoms (PFOA) and / or salts thereof are even more preferred. In the present disclosure, "substantially free" means that the mass concentration is preferably 50 ppb or less, more preferably less than 25 ppb, even more preferably 15 ppb or less, and particularly preferably less than 5 ppb. The lower limit is not particularly limited, and may be an amount below the detection limit.

[0068] In addition, examples of inorganic fine particles in the refrigerant leakage prevention agent include hydrophilic inorganic particles such as silica and zeolite (aluminum).

[0069] The above-mentioned refrigerant leakage prevention agent may be mixed with the above-mentioned refrigerating machine oil, for example, and sealed in the refrigerant circuit 10. As an example, the mixture of refrigerating machine oil and refrigerant leakage prevention agent can be obtained by appropriately pulverizing resin powder having a wide particle size distribution and mixing the resin powder so as to disperse it in the refrigerating machine oil. The pulverizing method and the dispersing / mixing method may be any appropriate known method, and for example, a homogenizer, a roll mill, a sand mill, etc. may be used.

[0070] This allows the refrigerant leakage prevention agent to be contained in the refrigerating machine oil at an appropriate content. For example, the lower limit of the refrigerating machine oil is preferably 0.0001 part by mass, more preferably 0.001 part by mass, even more preferably 0.01 part by mass, and particularly preferably 0.1 part by mass, per 100 parts by mass of the refrigerating machine oil. The upper limit is preferably 20 parts by mass, more preferably 10 parts by mass, even more preferably 5 parts by mass, and particularly preferably 3 parts by mass. If the amount is less than 0.0001 part by mass, the effect of substantially completely sealing holes that cause refrigerant leakage will be reduced. If the amount exceeds 20 parts by mass, the viscosity of the refrigerating machine oil will increase, and the fluidity of the refrigerating machine oil will decrease.

[0071] <Installation procedure> In the installation work for forming the refrigerant circuit 10 at the installation site of the air conditioner 1, the refrigerant circuit 10 is filled with refrigerant, odor components, refrigeration oil, refrigerant leakage prevention agent, etc., for example, according to the procedure shown in FIG.

[0072] During the installation work, the worker first installs the outdoor unit 20 and the indoor unit 30 at appropriate positions at the installation site, and then connects the first connecting pipe 11 and the second connecting pipe 12 to the outdoor unit 20 and the indoor unit 30, thereby forming the refrigerant circuit 10 (step S101).

[0073] Next, the worker fills the refrigerant circuit 10 with a mixture of refrigerating machine oil and a refrigerant leakage prevention agent that has been mixed in advance (step S102). For example, the compressor 21 is provided with a filling port with a check valve (not shown) for filling with refrigerating machine oil, and the worker fills the compressor 21 with the mixture by connecting a container (not shown) that stores the mixture to this filling port. In this way, the refrigerating machine oil and the refrigerant leakage prevention agent are sealed inside the compressor 21.

[0074] Thereafter, the worker fills the refrigerant and odor components into the refrigerant circuit 10 via the gas service port 44 of the outdoor unit 20 (step S103). For example, in filling the refrigerant and odor components, the worker connects a hose connected to a tank of odor components, a compound pressure meter, and a vacuum pump to the gas service port 44, and performs evacuation using the vacuum pump. Furthermore, the worker connects a refrigerant cylinder to the compound pressure meter instead of the vacuum pump, and pressure-feeds the refrigerant from the cylinder to the compound pressure meter, the odor component tank, and the gas service port 44 in this order. This allows the refrigerant and odorant to be filled into the refrigerant circuit 10 together during installation.

[0075] In the above description, the refrigerant circuit 10 is first filled with the refrigerating machine oil and the refrigerant leakage prevention agent, and then filled with the refrigerant and odor components. However, this procedure may be reversed. In other words, step S102 and step S103 may be performed in the reverse order.

[0076] <Effects of refrigerant leak prevention agent> Next, the action of the refrigerant leakage prevention agent sealed in the refrigerant circuit 10 will be described with reference to Figures 4(A) to 4(D). Figures 4(A) to 4(D) show an example in which a gap 22c occurs in a heat transfer tube 22t of the outdoor heat exchanger 22. For example, corrosion due to condensation in the heat transfer tube 22t progresses from the outer circumferential surface in an ant nest-like pattern.

[0077] As shown in Fig. 4(B), ant nest-like corrosion progresses gradually as, for example, condensation penetrates deep into the wall. The wall thickness of the heat transfer tube 22t becomes thinner as corrosion progresses, and the heat transfer tube 22t is subjected to pressure from the refrigerant flowing through the flow path 22a. Due to these effects, when corrosion progresses to a certain extent, holes, which are gaps 22c, are formed in the heat transfer tube 22t so as to penetrate the wall.

[0078] As shown in Figures 4(A) and 4(C), gap 22c connects the outside of heat transfer tube 22t with flow path 22a, allowing the refrigerant and odorous components to flow out of flow path 22a. However, the diameter or hydraulic diameter of gap 22c formed in heat transfer tube 22t is very small, and only a small amount of refrigerant and odorous components escape. Even if a highly flammable refrigerant is used, the refrigerant will not significantly burn.

[0079] The refrigerant leakage prevention agent 100 sealed in the refrigerant circuit 10 circulates through the refrigerant circuit 10 together with the refrigerant and odorous components when no gaps 22c as shown in FIG. 4(B) are formed. When gaps 22c are formed in the heat transfer tubes 22t, the fine particles of the refrigerant leakage prevention agent 100 enter the gaps 22c together with the refrigerant and begin to aggregate in the gaps 22c, as shown in FIG. 4(C). The multiple particles of the refrigerant leakage prevention agent 100 that have entered the gaps 22c then fill the gaps 22c. This allows the refrigerant leakage prevention agent 100 to prevent leakage of the refrigerant and odorous components from the flow path 22a.

[0080] For example, when PTFE resin, a fluorine-containing resin, is used as the refrigerant leakage prevention agent 100, the fine particles of the refrigerant leakage prevention agent 100 that have moved into the gap 22c disperse in the refrigerant or refrigerating machine oil to form a suspension, increasing the viscosity. Furthermore, the viscosity of the suspension increases as the diameter decreases within the gap 22c, forming a solid or semi-solid sealant Se. The sealant Se thus formed in the gap 22c fills the gap 22c, preventing leakage of the refrigerant and odorous components.

[0081] Furthermore, for example, when a silicon-containing resin is used as the refrigerant leakage prevention agent 100, the fine particles of the refrigerant leakage prevention agent 100 can react with the moisture of condensation that has entered the gap 22c to form a sealant Se. By forming the sealant Se using moisture in this way, the refrigerant leakage prevention agent 100 can more smoothly seal the gap 22c.

[0082] Alternatively, the refrigerant leakage prevention agent 100 may be a compound containing a polymeric monomer that undergoes a polymerization reaction to form the sealant Se. For example, the refrigerant leakage prevention agent 100 forms a polymer by a polymerization reaction between particles generated in the gap 22c due to corrosion of the pipe and the polymeric monomer, and the gap 22c can be filled with this polymer. The polymeric monomer may be a fluorine-containing resin, a silicon-containing resin, or the like. Examples of the polymeric monomer include alkoxysilane, acetoxysilane mercaptosilane, and aminosilane.

[0083] The air conditioner 1 according to this embodiment is basically configured as described above, and the effect of the refrigerant leakage prevention agent 100 when a gap 22c occurs in the refrigerant circuit 10 will be described below with reference to Figures 5(A) and 5(B). Figure 5(A) shows a pattern in which a first gap, which is a minute hole, occurs in the piping of the refrigerant circuit 10. On the other hand, Figure 5(B) shows a pattern in which a second gap, which is a hole larger than the first gap, occurs in the piping of the refrigerant circuit 10.

[0084] In the pattern of Fig. 5(A), for example, a first gap (gap 22c) penetrating the wall of the heat transfer tube 22t of the outdoor heat exchanger 22 constituting the refrigerant circuit 10 occurs due to corrosion caused by aging or the like (step S201: also see Fig. 4(A)). In this case, the first gap is small enough to allow a slight leakage of the refrigerant and odor components from the flow path 22a, and its diameter or hydraulic diameter is sufficiently small.

[0085] As this first gap is generated, the fine particles of the refrigerant leakage prevention agent 100 sealed in the refrigerant circuit 10 flow through the refrigerant circuit 10 and enter the first gap (step S202: see also FIG. 4(B)). In the first gap, the fine particles of the refrigerant leakage prevention agent 100 aggregate, guided by the flow of refrigerant escaping through this first gap.

[0086] The refrigerant leakage prevention agent 100 that has flowed into the first gap then becomes a suspension in the minute first gap, increasing its viscosity, and remains in the first gap, thereby blocking the first gap (step S203). This allows the refrigerant leakage prevention agent 100 to easily prevent leakage of refrigerant and odorous components from the refrigerant circuit 10 to the outside. For example, the refrigerant leakage prevention agent 100 can fill first gaps with a diameter or hydraulic diameter of approximately 30 μm or less, thereby blocking leakage of refrigerant and odorous components.

[0087] 5(A), for example, a second gap penetrating the wall of the heat transfer tube 22t of the outdoor heat exchanger 22 constituting the refrigerant circuit 10 occurs (step S301). The diameter or hydraulic diameter of this second gap is larger than the diameter or hydraulic diameter of the first gap, and the second gap allows more refrigerant and odor components from the flow path 22a to leak than the first gap. With the occurrence of this second gap, particles of the refrigerant leakage prevention agent 100 sealed in the refrigerant circuit 10 also enter the second gap, but because the second gap is large, the refrigerant and odor components escape to the outside through the second gap.

[0088] Therefore, the particles of the refrigerant leakage prevention agent 100 do not block the second gap, and the refrigerant and odorous components continue to leak from the second gap (step S302).

[0089] A person around the air conditioner 1 can use their sense of smell to detect the odorous components leaking from this second gap and thereby become aware of the occurrence of the second gap in the refrigerant circuit 10, in other words, of a broken pipe (step S303). This allows the person who notices the refrigerant leak to take necessary measures early on, such as performing maintenance on the air conditioner 1 or keeping flammable objects away.

[0090] As described above, when a first gap occurs, the air conditioner 1 automatically repairs the first gap with the refrigerant leakage prevention agent 100. As a result, the refrigerant leakage prevention agent 100 reduces the effort required to repair the refrigerant circuit 10 and can prevent the release of unpleasant odors from odorous components into the surrounding area. On the other hand, in the case of a large refrigerant leak due to a second gap, people nearby who recognize the odorous components can be prompted to take appropriate action.

[0091] The refrigeration device 1 according to the present disclosure is not limited to the above embodiment and may take various modified forms. For example, the refrigerant leakage prevention agent 100 is not limited to being mixed with refrigeration oil and then filled into the refrigerant circuit 10, but may be filled into the refrigerant circuit 10 without being mixed with other substances. Alternatively, the refrigerant leakage prevention agent 100 may be filled into the refrigerant circuit 10 when the refrigerant is filled. In this case, the refrigerant leakage prevention agent may be mixed with a liquid odorous component in advance, and the refrigerant may be circulated through a tank of this mixture, thereby filling the refrigerant circuit 10 with the refrigerant leakage prevention agent together with the odorous component.

[0092] <Flare connection part> The gaps that occur in the refrigerant circuit 10 are not limited to holes that penetrate the wall of the pipes. For example, as shown in Fig. 7, in a flare connection 15 that connects a first pipe 10a and a second pipe 10b that constitute the refrigerant circuit 10 by a flare connection, if the flare connection is weak, a gap 15c may occur over time, resulting in a slight leakage of refrigerant. Alternatively, the gap 15c in the flare connection 15 may also occur due to poor construction during the initial connection stage.

[0093] Specifically, flare connection portion 15 has a first connector 16 that forms the end of first pipe 10a, and a second connector 17 that forms the end of second pipe 10b and is connected to first connector 16. Second connector 17 also has a flare nut 18 that screws onto a male thread portion formed on the outer peripheral surface of first connector 16.

[0094] Examples of loose flare connections include when the tip of first connector 16 and the flared portion of second connector 17, which are in contact with each other, separate, or when flare nut 18 becomes loose. As shown in Figure 7(A), refrigerant and odorous components leak from gap 15c that occurs between first connector 16 and second connector 17.

[0095] 7(B), the refrigerant leakage prevention agent 100 sealed in the refrigerant circuit 10 begins to aggregate in the gap 15c of the flare connection 15, in other words, in the separated portion and screwed portion between the first connector 16 and the second connector 17. The refrigerant leakage prevention agent 100 fills the gap, thereby preventing leakage of the refrigerant and odorous components from the flare connection 15.

[0096] <Aspects and Effects of the Present Disclosure> The above-disclosed embodiment has, for example, the following aspects and effects.

[0097] One aspect of the present disclosure is a refrigeration device 1 having a refrigerant circuit 10, in which a highly flammable refrigerant, an odorous component, and a refrigerant leakage prevention agent 100 are sealed, and the refrigerant leakage prevention agent 100 repairs gaps that occur in the refrigerant circuit 10 and have a diameter or hydraulic diameter of 30 μm or less.

[0098] As described above, the refrigeration apparatus 1 can easily repair minute gaps that occur in the refrigerant circuit 10 using the refrigerant leakage prevention agent 100 sealed in the refrigerant circuit 10. That is, the refrigeration apparatus 1 automatically fills gaps in the refrigerant circuit 10 that are 30 μm or smaller with the refrigerant leakage prevention agent 100 to prevent leakage of odorous components. On the other hand, if a large amount of refrigerant leaks through a gap that is larger than 30 μm, the refrigeration apparatus 1 can make nearby people aware of the refrigerant leak by using the odorous components. In other words, by combining the odorous components and the refrigerant leakage prevention agent, the refrigeration apparatus 1 can selectively repair the refrigerant circuit 10 or alert nearby people.

[0099] The refrigerant circuit 10 also includes a heat exchanger (outdoor heat exchanger 22), and the gap 22c is a hole formed in a heat transfer tube 22t of the heat exchanger.

[0100] As a result, the refrigeration apparatus 1 can easily close the gaps 22c occurring in the heat transfer tubes 22t with the refrigerant leakage prevention agent 100.

[0101] The refrigerant circuit 10 also has at least two pipes and a flare connection 15 that connects the at least two pipes, and the gap 15c is formed in the flare connection 15.

[0102] As a result, in the refrigeration apparatus 1, the gap 15c occurring in the flare connection portion 15 can also be easily closed by the refrigerant leakage prevention agent 100.

[0103] The refrigerant leakage prevention agent 100 is made of organic or inorganic fine particles that aggregate in the gaps 15c and 22c and fill the gaps 15c and 22c.

[0104] The organic or inorganic fine particles allow the refrigeration device 1 to create a suspension in the gaps 15c and 22c, thereby blocking the gaps 15c and 22c.

[0105] The organic or inorganic fine particles include fluorine-containing resins or silicon-containing resins.

[0106] As a result, the refrigeration device 1 can continuously maintain the properties of the refrigerant leakage prevention agent 100 filled in the refrigerant circuit 10, and can smoothly aggregate the agent if gaps occur.

[0107] The refrigerant leakage prevention agent 100 is a compound that reacts with moisture to form a sealant Se.

[0108] As a result, the refrigerant leakage prevention agent 100 forms a sealant Se with the moisture inside the gaps 15c and 22c, and can close the gaps 15c and 22c.

[0109] The refrigerant leakage prevention agent 100 is a compound containing a polymer monomer that undergoes a polymerization reaction to form a sealant.

[0110] In this case as well, the refrigerant leakage prevention agent 100 forms a sealant Se inside the gaps 15c and 22c, thereby sealing the gaps 15c and 22c.

[0111] The refrigerant is a refrigerant whose main component is a hydrocarbon.

[0112] This makes it possible to avoid environmental pollution even if the refrigerant is released from the refrigerant circuit 10 into the atmosphere.

[0113] Moreover, the odorous components are compounds containing sulfur.

[0114] This allows people in the vicinity to easily become aware of any leakage of refrigerant and odorous components from the refrigerant circuit 10.

[0115] The odorous components include one or more of tetrahydrothiophene, dimethyl sulfide, and ethyl methyl sulfide.

[0116] As a result, the odorous components have superior odor quality and odor threshold compared to other sulfide-based components, and are chemically stabilized, so that the composition of the odorous components can be well maintained in the refrigerant circuit 10.

[0117] The refrigeration device 1 according to the presently disclosed embodiment is illustrative in all respects and not restrictive. The embodiment may be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above-described embodiments may be configured differently within a consistent range, and may be combined within a consistent range.

[0118] For example, the refrigeration device 1 may be a device that circulates a refrigerant other than the air conditioner 1. As an example, the refrigeration device 1 can be applied to a cooling device that cools a refrigerator or a freezer, a chiller unit, a heat pump type water heater, etc. [Explanation of symbols]

[0119] 1. Refrigeration equipment (air conditioning equipment) 10 Refrigerant circuit 15 Flare connection 15c, 22c gap 22 Outdoor heat exchanger 22c gap 22t heat transfer tube 44 Gas service port 100 Refrigerant leak prevention agent

Claims

1. A refrigeration system (1) having a refrigerant circuit (10), The refrigerant circuit (10) contains a highly flammable refrigerant, an odorous component, and a refrigerant leakage prevention agent (100), The refrigerant leakage prevention agent (100) repairs gaps (15c, 22c) having a diameter or hydraulic diameter of 30 μm or less that occur in the refrigerant circuit (10). Refrigeration equipment.

2. The refrigerant circuit (10) includes a heat exchanger (22), The gap (22c) is a hole formed in the heat transfer tube (22t) of the heat exchanger (22). The refrigeration system of claim 1.

3. The refrigerant circuit (10) has at least two pipes (10a, 10b) and a flare connection (15) connecting at least the two pipes (10a, 10b), The gap (15c) is formed in the flare connection portion (15). The refrigeration system of claim 1.

4. The refrigerant leakage prevention agent (100) is organic or inorganic fine particles that aggregate in the gaps (15c, 22c) and fill the gaps (15c, 22c). The refrigeration system according to any one of claims 1 to 3.

5. The organic or inorganic fine particles include a fluorine-containing resin or a silicon-containing resin.

5. The refrigeration system of claim 4.

6. The refrigerant leakage prevention agent (100) is a compound that reacts with moisture to form a sealant. The refrigeration system according to any one of claims 1 to 3.

7. The refrigerant leakage prevention agent (100) is a compound containing a polymer monomer that undergoes a polymerization reaction to form a sealant. The refrigeration system according to any one of claims 1 to 3.

8. The highly flammable refrigerant is a refrigerant mainly composed of a hydrocarbon. The refrigeration system according to any one of claims 1 to 3.

9. The odor component is a compound containing sulfur. The refrigeration system according to any one of claims 1 to 3.

10. The odor component includes any one of tetrahydrothiophene, dimethyl sulfide, and ethyl methyl sulfide, or one or more of these as a component.

10. The refrigeration device of claim 9.

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