Method for treating working fluid and device for treating working fluid

Abstract

The present invention provides a method for treating a working fluid, the method improving the amount of odorant that is separated. The method for treating a working fluid comprises a step (S1c) for preparing a working fluid and a step (S2c) for separating an odorant from a coolant. The working fluid contains a coolant, a refrigerating machine oil, and an odorant. The boiling point Tb1 of the odorant is higher than the boiling point Tb2 of the coolant. In the separation step (S1c), the temperature of the working fluid is maintained at a temperature higher than boiling point Tb1 of the coolant but lower than boiling point Tb2 of the odorant.

Description

Method and apparatus for treating working fluid

[0001] The present disclosure relates to a method and apparatus for treating a working fluid.

[0002] Conventionally, refrigerants used in refrigeration cycle devices contain odorants so that they can be recognized by the sense of smell (see International Publication No. WO 2021 / 166028).

[0003] International Publication No. 2021 / 166028

[0004] However, since odorants contained in refrigerants, which are an example of working fluids, may remain in the gas phase, there is room for improvement in separating the odorants from the refrigerants.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a method and a treatment device for treating a working fluid in which the amount of odorant separated is improved.

[0006] A method for treating a working fluid according to the present disclosure includes the steps of preparing a working fluid and separating an odorant from a refrigerant. The working fluid includes a refrigerant, a refrigeration oil, and an odorant. The odorant has a boiling point higher than that of the refrigerant. In the separating step, the temperature of the working fluid is maintained above the boiling point of the refrigerant but below the boiling point of the odorant.

[0007] A treatment device according to the present disclosure is a treatment device for treating a working fluid. The working fluid includes a refrigerant, a refrigeration oil, and an odorant. The odorant has a boiling point higher than that of the refrigerant. The treatment device is configured to separate the gaseous refrigerant from the liquid odorant by cooling the working fluid to a temperature higher than the boiling point of the refrigerant but lower than the boiling point of the odorant.

[0008] A processing device according to the present disclosure includes a cooling unit and a separation unit. The cooling unit cools a working fluid. The working fluid includes a refrigerant, refrigeration oil, and an odorant. In the cooled working fluid, the separation unit separates the odorant from the refrigerant. The boiling point of the odorant is higher than the boiling point of the refrigerant. The cooling unit cools the temperature of the working fluid to above the boiling point of the refrigerant but below the boiling point of the odorant. The separation unit separates the gaseous refrigerant from the liquid odorant.

[0009] According to the above, it is possible to obtain a method and an apparatus for treating a working fluid in which an increased amount of odorant is separated.

[0010] 1 is a schematic diagram showing an example of a refrigeration cycle apparatus (closed refrigerant circuit) according to embodiment 1. FIG. 2 is a schematic diagram of a separation unit in the refrigeration cycle apparatus according to embodiment 1. FIG. 3 is a flowchart of a refrigerant discharge method in the refrigerant cycle apparatus according to embodiment 1. FIG. 4 is a flowchart of a refrigerant discharge method in the refrigerant cycle apparatus according to embodiment 2. FIG. 5 is a schematic diagram showing an example of a processing device according to embodiment 3. FIG. 6 is a schematic diagram of a separation unit in the processing device according to embodiment 3. FIG. 7 is a flowchart of a working fluid processing method in the processing device according to embodiment 3.

[0011] Hereinafter, embodiments of the present disclosure will be described. Unless otherwise specified, the same or corresponding parts in the following drawings will be denoted by the same reference numerals, and the description thereof will not be repeated.

[0012] Embodiment 1. <Configuration of refrigeration cycle apparatus (refrigerant circuit)> Fig. 1 is a schematic diagram showing an example of a refrigeration cycle apparatus (closed refrigerant circuit 100) according to embodiment 1. Fig. 2 is a schematic diagram of a separation unit 15 in the refrigeration cycle apparatus according to embodiment 1.

[0013] The refrigeration cycle device is, for example, a refrigeration cycle device for air conditioning, and as shown in Fig. 1, mainly comprises an outdoor unit 1 and an indoor unit 2. The outdoor unit 1 and the indoor unit 2 are connected using a liquid pipe 9 and a gas pipe 10.

[0014] The outdoor unit 1 has a compressor 3, a condenser 4, and an outdoor blower 5. The compressor 3 is connected to the condenser 4 by piping. The indoor unit 2 has an expansion valve 6, an evaporator 7, and an indoor blower 8. The expansion valve 6 is connected to the evaporator 7 by piping.

[0015] The compressor 3 of the outdoor unit 1 and the evaporator 7 of the indoor unit 2 are connected by a gas pipe 10. The condenser 4 of the outdoor unit 1 and the expansion valve 6 of the indoor unit 2 are connected by a liquid pipe 9. This configuration of the refrigeration cycle device forms a closed refrigerant circuit 100. Refrigerant and odorant circulate within the closed refrigerant circuit 100 via the liquid pipe 9 and the gas pipe 10.

[0016] The compressor 3 compresses the gaseous refrigerant and odorant in the gas pipe 10. The condenser 4 cools the gaseous refrigerant and odorant compressed by the compressor 3, thereby changing the refrigerant and odorant from a gaseous state to a high-pressure liquid state or a two-phase gas-liquid state. The expansion valve 6 depressurizes the high-pressure liquid state or the two-phase gas-liquid state refrigerant and odorant. The evaporator 7 heats the depressurized refrigerant and odorant to change them to a low-pressure gaseous state. The compressor 3 draws in the refrigerant and odorant that have been changed to a low-pressure gaseous state by the evaporator 7 and compresses them again.

[0017] The closed refrigerant circuit 100 may be provided with any one of an accumulator, a suction muffler, and a receiver between the compressor 3 and the evaporator 7. The accumulator and the suction muffler are devices that separate liquid and gas and supply the gas to the compressor. The receiver is a device that stores the liquid refrigerant liquefied in the condenser 4. The provision of the accumulator, the suction muffler, and the receiver prevents a large amount of liquid refrigerant from flowing into the compressor 3. As a result, it is possible to prevent the refrigeration oil from being excessively diluted and the lubrication of the sliding parts of the compressor 3 from being deteriorated.

[0018] Refrigerating machine oil is contained inside the compressor 3. The refrigerating machine oil maintains the lubrication of the sliding parts of the compressor 3. The refrigerating machine oil is discharged into the gas pipe 10 together with the refrigerant and odorant compressed by the sliding parts of the compressor 3. Therefore, the refrigerating machine oil circulates within the closed refrigerant circuit 100 together with the refrigerant and odorant.

[0019] The outdoor fan 5 sends air to the condenser 4. The outdoor fan 5 is provided to facilitate heat exchange between the refrigerant flowing through the condenser 4 and the air, thereby facilitating heat absorption or release. The indoor fan 8 sends air to the evaporator 7. The indoor fan 8 is provided to facilitate heat exchange between the refrigerant flowing through the evaporator 7 and the air, thereby facilitating heat absorption or release.

[0020] In the refrigeration cycle apparatus according to the first embodiment, the condenser 4 and the evaporator 7 are heat exchangers that exchange heat with air. In the refrigeration cycle apparatus according to the first embodiment, the condenser 4 and the evaporator 7 may exchange heat with a liquid such as water instead of air.

[0021] In the refrigeration cycle device of this embodiment 1, the evaporator 7 is provided in the indoor unit 2 and the condenser 4 is provided in the outdoor unit 1, but for example, the evaporator 7 may be provided in the outdoor unit 1 and the condenser 4 may be provided in the indoor unit 2.

[0022] The expansion valve 6 may be provided in the outdoor unit 1 instead of in the indoor unit 2. The expansion valve 6 may be provided in both the outdoor unit 1 and the indoor unit 2. A plurality of indoor units 2 may be provided in the closed refrigerant circuit 100. A plurality of outdoor units 1 may be provided in the closed refrigerant circuit 100.

[0023] The outdoor unit 1 as described above may be provided with, for example, a switching mechanism (not shown). The switching mechanism switches between the suction pipe and the discharge pipe of the compressor 3 by arranging a four-way valve or a combination of multiple valves. By providing the switching mechanism, the heat exchanger in the outdoor unit 1 can function as an evaporator, and the heat exchanger in the indoor unit 2 can function as a condenser. In this way, the refrigeration cycle device can be used as a heater that uses outdoor heat to heat the room.

[0024] The refrigeration cycle device may be, for example, a device capable of both cooling and heating, a device capable of only cooling, or a device capable of only heating.

[0025] The use of the refrigeration cycle apparatus according to the first embodiment is not limited to air conditioning, but may also be used for freezing, refrigeration, or hot water supply.

[0026] The outdoor unit 1 has a gas pipe side operation valve 11, a liquid pipe side operation valve 17, and a service port 12. The gas pipe side operation valve 11 is provided in a gas pipe 10 connecting the evaporator 7 and the compressor 3. The liquid pipe side operation valve 17 is provided in a liquid pipe 9 connecting the condenser 4 and the expansion valve 6. By opening and closing the gas pipe side operation valve 11 and the liquid pipe side operation valve 17, the refrigerant can be charged into or discharged from the closed refrigerant circuit 100.

[0027] As shown in Fig. 1, the service port 12 is connected to a gas pipe 10 via a gas pipe side operation valve 11. The gas pipe side operation valve 11 can be opened to allow the refrigerant and odorant to be discharged outside the closed system. At this time, the refrigerant and odorant pass through the service port 12 and are supplied to a discharge device such as a treatment device 13a (see Fig. 5).

[0028] When the refrigerant in the closed refrigerant circuit 100 is discharged to the outside of the closed system, the service port 12 is connected to a discharge device (discharge path 13) via a hose or the like. The discharge device has a cooling unit 14 and a separation unit 15. The refrigerant and odorant that have passed through the service port 12 are supplied to the cooling unit 14. The refrigerant and odorant are cooled in the cooling unit 14.

[0029] The refrigerant and odorant cooled by the cooling unit 14 are supplied to the separation unit 15. The refrigerant and odorant supplied to the separation unit 15 are separated into a gaseous refrigerant and a liquid odorant by the separation unit 15. As shown in FIG. 1 , the cooling unit 14 and the separation unit 15 may be configured independently of each other, or the cooling unit 14 may include the separation unit 15. In other words, the cooling unit 14 may cool the separation unit 15. In this way, the cooling and separation of the refrigerant and odorant can be performed simultaneously.

[0030] The odorant cooled by the cooling unit 14 is in a state of gas-liquid equilibrium. That is, an amount of odorant corresponding to the saturated vapor pressure of the odorant at the temperature during cooling is contained in the gaseous refrigerant (in the gas phase). Therefore, when the refrigerant is discharged to the outside of the closed system, the odorant remains in the gas phase, and a portion of the odorant is discharged together with the refrigerant.

[0031] Here, a feature of the refrigerant discharge method according to the first embodiment is that the refrigerant and odorant are discharged together with the refrigerating machine oil. By discharging the refrigerant and odorant together with the refrigerating machine oil, the liquid odorant is contained in the refrigerating machine oil in the separation unit 15. When the liquid odorant is contained in the refrigerating machine oil, a drop in the vapor pressure of the odorant occurs. The occurrence of a drop in the vapor pressure of the odorant means that the saturated vapor pressure of the odorant decreases, and the amount of odorant contained in the gas phase decreases. In other words, the occurrence of a drop in the vapor pressure of the odorant increases the amount of odorant separated from the gaseous refrigerant in the separation unit 15, and the amount of odorant discharged outside the closed system together with the refrigerant can be reduced.

[0032] Here, the cooling unit 14 will be described in detail. In the cooling unit 14, the refrigerant, odorant, and refrigeration oil are cooled to a temperature Tc. The temperature Tc is higher than the normal boiling point Tb1 of the refrigerant and lower than the normal boiling point Tb2 of the odorant. In this manner, in the cooling unit 14, the gaseous refrigerant is not liquefied, but the odorant is liquefied.

[0033] The temperature Tc is preferably higher than the standard melting point Tm2 of the odorant. In this way, the odorant does not solidify, and clogging of the exhaust path 13 can be suppressed.

[0034] The cooling method in the cooling unit 14 is not particularly limited, and may be a cooling method by heat exchange or a cooling method by adiabatic expansion. Specifically, the cooling method by heat exchange is a method of cooling a fluid passing through the discharge path 13 by heat exchange between the fluid and the outside. The cooling method by adiabatic expansion is a method of cooling a fluid passing through the discharge path 13 by adiabatic expansion. The fluid referred to here is a refrigerant, an odorant, and a refrigerating machine oil.

[0035] The cooling method by heat exchange may be, for example, a method in which heat exchange is performed by bringing the exhaust path 13 into contact with a low-temperature medium. Heat exchange is performed by exposing at least a portion of the components constituting the exhaust path 13 to a medium such as a low-temperature gas or liquid. The low-temperature medium is preferably a substance that is inactive to the components constituting the exhaust path 13. This prevents a decrease in the strength of the exhaust path 13 and rapid deterioration.

[0036] When the cooling method in the cooling unit 14 is a heat exchange cooling method, it is preferable that at least a portion of the cooling unit 14 is made of a material with high thermal conductivity. This allows the fluid passing through the discharge path 13 to be efficiently cooled. An example of a material with high thermal conductivity is metal. Among metals, aluminum, iron, copper, and the like have particularly high thermal conductivity and low reactivity with the refrigerant. Therefore, it is preferable that the material constituting at least a portion of the cooling unit 14 be aluminum, iron, copper, or an alloy containing at least one of these as a main component.

[0037] In the cooling method using heat exchange, heat exchange may be performed using a refrigeration cycle device (second refrigeration cycle device) separate from the refrigeration cycle device that discharges the refrigerant. Specifically, the fluid passing through the discharge path 13 may be cooled by heat exchange with the evaporator of the second refrigeration cycle device. In this case, the components constituting the discharge path 13 and the components constituting the evaporator of the second refrigeration cycle device are preferably made of materials primarily composed of the same metal. In this way, galvanic corrosion does not occur in the components constituting the discharge path 13 and the evaporator of the second refrigeration cycle device.

[0038] The refrigerant, odorant, and refrigerating machine oil cooled in this manner are supplied to the separation section 15.

[0039] Next, a specific description will be given of the separation unit 15. In order to prevent the odorant liquefied in the cooling unit 14 from being discharged from the discharge path 13 to the outside of the closed system, the liquid and gas are separated in the separation unit 15, and only the gas is discharged to the outside of the closed system.

[0040] The separation method in the separation section 15 is not particularly limited, but may be any of a separation method that utilizes the density difference between gas and liquid, a separation method that utilizes surface tension, a separation method that utilizes centrifugal force, etc.

[0041] The separation method utilizing the density difference between gas and liquid is a method of separating liquid and gas by utilizing the fact that the density of the liquid is greater than the density of the gas, as shown in Fig. 2, for example. Specifically, a refrigerant, an odorant, and refrigerating machine oil are supplied to a separation container 16. The liquid is stored in the lower part of the separation container 16. The gas is discharged outside the closed system.

[0042] The separated liquid contains the odorant liquefied in the cooling unit 14 and the refrigerating machine oil. The mixing of the refrigerating machine oil and the odorant as liquids causes a vapor pressure drop of the odorant. The vapor pressure drop of the odorant in the separation unit 15 reduces the amount of odorant present in the gas phase of the separation container 16. In other words, compared to when no refrigerating machine oil is present in the separation unit 15, the amount of gaseous odorant discharged to the outside of the closed system together with the refrigerant is reduced, and the odor of the discharged gaseous refrigerant is reduced. As long as the odorant and the refrigerating machine oil are in contact with each other, a vapor pressure drop of the odorant occurs. Therefore, both the separation method utilizing surface tension and the separation method utilizing centrifugal force can achieve the effect of reducing the amount of odorant discharged by utilizing a vapor pressure drop.

[0043] The separation container 16 may include a liquid level indicator and a liquid discharge unit (not shown). The liquid level indicator displays the height of the liquid level inside the separation container 16. The liquid discharge unit enables the liquid stored inside the separation container 16 to be discharged. The liquid stored inside the separation container 16 is discharged by opening and closing the container.

[0044] When the liquid level in the separation container 16 rises above a predetermined height, the stored liquid may be discharged, thereby discharging the liquid odorant, thereby preventing the discharge of gaseous refrigerant with a strong odor.

[0045] The separation container 16 may also include a member (not shown) that can capture the odorant in the separation container 16 by adsorption or absorption. This further removes the odorant in the gas phase. As a result, the odor of the discharged gaseous refrigerant is reduced.

[0046] In a separation method that utilizes the density difference between gas and liquid, the configuration of the separation unit 15 does not have to be the configuration shown in Fig. 2. The configuration of the separation unit 15 may be, for example, a configuration that includes a space in which the diameter of a part of the pipe that constitutes the discharge path 13 is enlarged, or a configuration that includes a baffle-type oil separator.

[0047] The amount of refrigerating machine oil discharged may be increased by rapidly opening the gas pipe side operating valve 11 to the outside of the closed system. Specifically, when the gas pipe side operating valve 11 is rapidly opened, the pressure in the closed system refrigerant circuit 100 decreases, causing the refrigerant dissolved in the refrigerating machine oil in the compressor 3 to rapidly evaporate. The evaporation of the refrigerant causes the refrigerating machine oil to foam. In other words, the refrigerant contained in the refrigerating machine oil vaporizes, increasing the apparent volume of the refrigerating machine oil. As a result, the oil level of the refrigerating machine oil rises, and the amount of refrigerating machine oil flowing into the piping that forms the closed system refrigerant circuit 100 increases. As a result, the amount of refrigerating machine oil supplied to the discharge path 13 increases. This improves the effect of separating the odorant from the gaseous refrigerant by the refrigerating machine oil.

[0048] Here, when opening the gas pipe side operation valve 11, it is preferable to rapidly open the gas pipe side operation valve 11 so that the flow rate of the refrigerant discharged becomes greater than the evaporation rate of the refrigerant immediately after opening the gas pipe side operation valve 11. Specifically, the gas pipe side operation valve 11 is rapidly opened so that the flow rate of the refrigerant passing through the discharge path 13 becomes greater than the evaporation rate of the refrigerant contained in the liquid phase (including the refrigerating machine oil) in the closed system refrigerant circuit 100 immediately after opening the gas pipe side operation valve 11.

[0049] Furthermore, the refrigerating machine oil in the compressor 3 may be heated before or while the gas pipe side operation valve 11 is opened. By heating the refrigerating machine oil in the compressor 3, the refrigerant and odorant dissolved in the refrigerating machine oil evaporate. As a result, the refrigerating machine oil foams. That is, the oil level of the refrigerating machine oil rises, and the amount of refrigerating machine oil supplied to the discharge path 13 increases. In this way, the effect of separating the odorant from the gaseous refrigerant by the refrigerating machine oil can be improved.

[0050] In addition, by performing the rapid opening of the gas pipe side operation valve 11 in combination with the heating inside the compressor 3, the amount of refrigerating machine oil supplied to the discharge path 13 is further increased.

[0051] A filter may be provided in the discharge path 13, inside the separation unit 15, or in the piping outside the closed system from the separation unit 15. The filter prevents liquid from being discharged outside the closed system and allows gaseous refrigerant to pass through. This reduces the amount of odorant discharged outside the closed system and reduces the odor of the discharged gaseous refrigerant.

[0052] The filter is made of a material capable of absorbing odorants and refrigeration oil. The filter preferably has a highly breathable structure so as not to reduce the flow rate of the gaseous refrigerant. The filter may be made of, for example, a nonwoven fabric.

[0053] The gaseous refrigerant discharged from separation unit 15 is discharged either by recovery or by release into the atmosphere, depending on the refrigerant's global warming potential and legal regulations. The refrigerant is preferably recovered in a recovery container. However, if it is difficult to fill the recovery container with the refrigerant due to legal regulations or other reasons, the refrigerant is released into the atmosphere.

[0054] The refrigerant used in the refrigeration cycle device is preferably a fluid whose normal boiling point Tb1 is lower than the outside air temperature in the environment where the refrigerant is discharged. For example, when the outside air temperature is 15°C, the normal boiling point Tb1 of the refrigerant is preferably lower than 15°C. This allows the refrigerant in the closed refrigerant circuit 100 to be discharged to the outside by vapor pressure. In other words, there is no need to use a pump or the like to suction the refrigerant when discharging it.

[0055] Furthermore, the refrigerant is a fluid whose normal boiling point Tb1 is lower than the normal boiling point Tb2 of the odorant. As a result, in the cooling unit 14, the refrigerant and odorant are cooled to a temperature Tc between the normal boiling point Tb2 of the odorant and the normal boiling point Tb1 of the refrigerant, thereby selectively liquefying the odorant. As a result, only the gaseous refrigerant can be discharged outside the closed system. The refrigerant only needs to satisfy the above temperature relationship, and the material constituting the refrigerant may be either a halogenated hydrocarbon or a natural refrigerant, or a mixture thereof.

[0056] Examples of halogenated hydrocarbons include chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, fluoroiodocarbons, etc. Examples of refrigerants that can be used include HFC-23, HFC-32, HFC-41, HFC-125, HFC-134, HFC-134a, HFC-143, HFC-143a, HFC-152, HFC-152a, HFC-161, HFO-1141, HFO-1132a, HFO-1132(E), HFO-1132(Z), HFO-1123, HFO-1225ye(Z), H and HFO-1225ye(E), HFO-1225zc, HFO-1234yf, HFO-1234ze(E), HFO-1234ze(Z), HFO-1234ye(Z), HFO-1234ye(E), HFO-1243zf, HFO-1252zf, HFO-1261yf, FIC-13I1 (CF3I), HCFC-22, and CFC-12.

[0057] In particular, as a refrigerant with a low global warming potential, it is more preferable that the refrigerant to be used is, for example, any one of HFO-1132a, HFO-1132(E), HFO-1132(Z), HFO-1123, HFO-1225ye(Z), HFO-1225ye(E), HFO-1225zc, HFO-1234yf, HFO-1234ze(E), HFO-1234ze(Z), HFO-1234ye(Z), HFO-1234ye(E), HFO-1243zf, HFO-1252zf, HFO-1261yf, or FIC-13I1 (CF3I).

[0058] A natural refrigerant is a refrigerant that exists naturally in nature. Examples of natural refrigerants include carbon dioxide (R-744), ammonia (R-717), and hydrocarbons. A hydrocarbon is a refrigerant that is composed only of carbon and hydrogen. Examples of hydrocarbons include R-290 (propane), R-1270 (propylene), R-600 (butane), and R-600a (isobutane). These natural refrigerants have a low global warming potential and are therefore suitable as refrigerants for use in refrigeration cycle devices.

[0059] The odorant preferably has a distinctive odor. Because the odorant has a distinctive odor, the refrigerant mixed with the odorant can be detected by olfaction. Examples of materials constituting the odorant include mercaptans, sulfides, thiophenes, cyclohexene, acrylic esters, ammonia, amines, pyrazines, and norbornenes. Examples of mercaptans include methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, and tertiary butyl mercaptan. Examples of sulfides include dimethyl sulfide, diethyl sulfide, and methyl ethyl sulfide. Examples of thiophenes include tetrahydrothiophene. These odorants may be used alone or in combination of two or more. Furthermore, the materials constituting the odorant may contain a compound having a unique odor other than the above-mentioned materials.

[0060] The odorant is a material having a normal boiling point Tb2 higher than the normal boiling point Tb1 of the refrigerant. Thus, the cooling unit 14 can selectively liquefy the odorant by cooling the refrigerant and odorant to a temperature Tc between the normal boiling point Tb2 of the odorant and the normal boiling point Tb1 of the refrigerant. For example, when R-290 is used as the refrigerant, the normal boiling point Tb1 of R-290 is −42°C. Therefore, an odorant with a normal boiling point Tb2 higher than −42°C is used. For example, tetrahydrothiophene, which has a normal boiling point Tb2 of 121°C, or cyclohexene, which has a normal boiling point Tb2 of 83°C, is suitable as an odorant to be mixed with the R-290 refrigerant. When the odorant is a mixture of two or more compounds, the normal boiling points Tb2 of all of the odorants need only be higher than the normal boiling point Tb1 of the refrigerant.

[0061] When the refrigerant is a non-azeotropic refrigerant mixture, it is preferable that the normal boiling point Tb2 of the odorant be higher than the boiling point Tb1 of the refrigerant at atmospheric pressure. In this way, the refrigerant is not liquefied in the cooling unit 14, and the odorant can be selectively liquefied. For example, when R-454B is used as the refrigerant, R-454B has a dew point of −50.9°C at atmospheric pressure and a boiling point Tb1 at atmospheric pressure of −50.0°C. In this case, it is preferable to use an odorant whose normal boiling point Tb2 is higher than −50.0°C. Note that R-454B is a mixed refrigerant of R-32 and R-1234y, and the mass ratio of R-32 to R-1234y (=R-32 / R-1234yf) is 68.9% by mass / 31.1% by mass.

[0062] The refrigeration oil includes a base oil. The base oil includes at least one of an oxygen-containing oil and a hydrocarbon oil. Examples of the oxygen-containing oil include polyethylene glycol, polyol ester, and polyvinyl ether. Examples of the hydrocarbon oil include polyalphaolefin, alkylbenzene, alkylnaphthalene, and mineral oil.

[0063] The lubrication of the sliding parts of the compressor 3 depends greatly on the kinematic viscosity of the base oil contained in the refrigerating machine oil. The material constituting the base oil preferably has a kinematic viscosity higher than that of the refrigerant. The kinematic viscosity of the base oil at 40°C is 5 mm ２ / second or more 250mm ２ / sec or less. By adjusting the molecular structure and degree of polymerization of the materials constituting the base oil, the kinematic viscosity of the base oil can be made to fall within the above range. When the base oil has a kinematic viscosity higher than that of the refrigerant, the cooling efficiency of the refrigeration cycle device is not significantly reduced, and the lubrication of the sliding parts in the compressor 3 is maintained.

[0064] The base oil is preferably an oxygen-containing oil. Oxygen-containing oils have high polarity. Therefore, oxygen-containing oils can dissolve polar compounds. Here, the odorants exemplified as materials constituting the odorant have a nitrogen atom, an oxygen atom, a sulfur atom, or a carbon-carbon double bond in their chemical structure. In other words, the odorants described above are compounds with polarity due to an imbalance in charge. Therefore, refrigeration oils containing oxygen-containing oils can dissolve odorants. Because the odorant dissolves in refrigeration oils containing oxygen-containing oils, a vapor pressure drop of the odorant occurs. In other words, the vapor pressure drop of the odorant increases the amount of odorant separated in the separation unit 15. As a result, the odor of the discharged gaseous refrigerant can be reduced.

[0065] The pour point of the refrigerating machine oil is preferably lower than the temperature Tc of the refrigerant, odorant, and refrigerating machine oil in the cooling unit 14. When the pour point of the refrigerating machine oil is lower than the temperature Tc in the cooling unit 14, clogging in the discharge path 13 due to a decrease in the fluidity of the refrigerating machine oil can be prevented.

[0066] The refrigerating machine oil may contain, as oil additives, antioxidants, acid scavengers, extreme pressure agents (antiwear agents), oxygen scavengers, fluorescent agents, colorants, etc. However, in order to prevent clogging of the discharge path 13 by the oil additives, it is preferable that these oil additives do not precipitate when the refrigerating machine oil is cooled in the cooling section 14.

[0067] <Refrigerant Discharge Method> FIG. 3 is a flowchart of a refrigerant discharge method in the refrigeration cycle apparatus according to the first embodiment. In the refrigeration cycle apparatus according to the first embodiment, a step (S1a) of discharging the refrigerant is first performed. In this step (S1a), the refrigerant containing the odorant is supplied from the refrigeration cycle apparatus to a discharge device. Specifically, the gas pipe side operating valve 11 is opened so that the refrigerant and odorant in the closed refrigerant circuit 100 are discharged to the discharge device. At this time, the refrigerant and odorant are discharged together with the refrigeration oil. Note that, in the refrigerant and odorant used in the refrigeration cycle apparatus, the boiling point Tb2 of the odorant is higher than the boiling point Tb1 of the refrigerant. The refrigeration oil is preferably oxygenated oil.

[0068] When the gas pipe side operation valve 11 is opened, the gas pipe side operation valve 11 is rapidly opened so that the flow rate of the refrigerant discharged immediately after opening the gas pipe side operation valve 11 is greater than the evaporation rate of the refrigerant. Specifically, the gas pipe side operation valve 11 is rapidly opened so that the flow rate of the refrigerant passing through the discharge path 13 is greater than the evaporation rate of the refrigerant contained in the liquid phase (including the refrigerating machine oil) in the closed refrigerant circuit 100 immediately after opening the gas pipe side operation valve 11. Furthermore, the refrigerating machine oil in the compressor 3 may be heated before or while the gas pipe side operation valve 11 is opened.

[0069] Next, a step (S2a) of separating the odorant from the refrigerant is performed. In this step (S2a), the refrigerant, the odorant, and the refrigerating machine oil are cooled to separate the refrigerant and the odorant. The refrigerant, the odorant, and the refrigerating machine oil supplied to the discharge device are cooled to a temperature Tc between the boiling point Tb2 of the odorant and the boiling point Tb1 of the refrigerant. In this way, the gaseous refrigerant does not liquefy, but the odorant liquefies. Note that the temperature Tc is higher than the standard melting point Tm2 of the odorant. Therefore, clogging of the discharge path 13 due to solidification of the odorant is suppressed. In particular, when the refrigerating machine oil is oxygen-containing oil, the odorant dissolves in the refrigerating machine oil.

[0070] At this time, the refrigerant and odorant are supplied to the exhaust device together with the refrigerating machine oil. Therefore, the refrigerating machine oil contains a liquid odorant. When the refrigerating machine oil contains a liquid odorant, a drop in the vapor pressure of the odorant occurs. In other words, the drop in the vapor pressure of the odorant increases the amount of odorant separated in the exhaust device. As a result, compared to when the refrigerating machine oil is not exhausted, the amount of gaseous odorant exhausted outside the closed system together with the refrigerant decreases, and the odor of the exhausted gaseous refrigerant is reduced.

[0071] At this time, it is preferable that the temperature Tc is above the pour point of the refrigerating machine oil, which can prevent clogging of the discharge path 13 due to a decrease in the fluidity of the refrigerating machine oil.

[0072] In this way, the liquefied odorant and the gaseous refrigerant are separated, and the gaseous refrigerant is discharged outside the closed system.

[0073] <Effects> A refrigerant discharge method according to the present disclosure includes a step (S1a) of discharging a refrigerant containing an odorant from a refrigeration cycle device, and a step (S2a) of separating the odorant from the refrigerant after the discharging step (S1a). The boiling point Tb2 of the odorant is higher than the boiling point Tb1 of the refrigerant. In the discharging step (S1a), the refrigerant is discharged together with refrigeration oil. In the separating step (S2a), the refrigerant containing the odorant is cooled to a temperature Tc between the boiling point Tb2 of the odorant and the boiling point Tb1 of the refrigerant. The temperature Tc is higher than the melting point Tm2 of the odorant.

[0074] This causes a drop in the vapor pressure of the odorant. That is, the drop in the vapor pressure of the odorant increases the amount of odorant separated by the exhaust device. As a result, compared to when refrigeration oil is not exhausted, the amount of gaseous odorant exhausted to the outside of the closed system together with the refrigerant decreases, and the odor of the exhausted gaseous refrigerant is reduced.

[0075] In the refrigerant discharging method, in the separating step (S2a), the temperature Tc is higher than the pour point of the refrigerating machine oil. By doing so, the pour point of the refrigerating machine oil is lower than the temperature Tc, and therefore clogging of the discharge path 13 due to a decrease in the fluidity of the refrigerating machine oil can be prevented.

[0076] In the above-described refrigerant discharge method, the refrigerating machine oil is oxygen-containing oil. In this way, the refrigerating machine oil containing oxygen-containing oil can dissolve the odorant. Since the odorant dissolves in the refrigerating machine oil containing oxygen-containing oil, a vapor pressure drop of the odorant occurs. In other words, the vapor pressure drop of the odorant increases the amount of odorant that is liquefied. As a result, the odor of the discharged gaseous refrigerant can be reduced.

[0077] In the above-described refrigerant discharge method, the refrigeration cycle device includes a compressor 3. In the discharge step (S1a), refrigerating machine oil in the compressor 3 is foamed. By doing so, the oil level of the refrigerating machine oil rises, and the amount of refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0078] In the above-described refrigerant discharge method, the refrigeration cycle apparatus is connected to a discharge device via a gas pipe side operation valve 11. In the discharge step (S1a), the gas pipe side operation valve 11 is rapidly opened to foam the refrigerating machine oil in the compressor 3. In this way, the oil level of the refrigerating machine oil rises, and the amount of refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0079] In the above-described refrigerant discharge method, in the discharge step (S1a), the gas pipe side operation valve 11 is rapidly opened so that the flow rate of the discharged refrigerant is greater than the evaporation rate of the refrigerant immediately after opening the gas pipe side operation valve 11. By doing so, the oil level of the refrigerating machine oil rises, and the amount of refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0080] In the refrigerant discharge method, in the discharge step (S1a), the refrigerating machine oil in the compressor 3 is heated to foam the refrigerating machine oil. In this way, the oil level of the refrigerating machine oil rises, and the amount of refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0081] Embodiment 2. <Refrigerant Discharge Method> Figure 4 is a flowchart of a refrigerant discharge method in a refrigerant cycle apparatus according to embodiment 2. Figure 4 corresponds to Figure 3. The refrigerant discharge method in the refrigerant cycle apparatus shown in Figure 4 basically has the same configuration as the refrigerant discharge method in the refrigerant cycle apparatus shown in Figure 3, but differs in that pumping down is performed before discharging the refrigerant.

[0082] When the refrigerant is discharged outside the closed system using the refrigerant discharge method in the refrigeration cycle apparatus according to Embodiment 1, the vapor pressure in the closed system refrigerant circuit 100 is equilibrated with atmospheric pressure. When the vapor pressure in the closed system refrigerant circuit 100 is equilibrated with atmospheric pressure, the refrigerant and odorant in the closed system refrigerant circuit 100 are difficult to discharge. As a result, the odor of the odorant remains in the closed system refrigerant circuit 100. When the refrigeration cycle apparatus is disassembled for relocation, repair, or the like, with the odor of the odorant remaining in the closed system refrigerant circuit 100, the odor of the odorant is discharged outside the closed system.

[0083] Here, in order to further remove odorant remaining in the closed refrigerant circuit 100, pumping down may be performed before the refrigerant is discharged from the refrigeration cycle device. Specifically, before the refrigerant is discharged, a step (S1b) of recovering the refrigerant containing the odorant into the outdoor unit and a step (S2b) of closing the outdoor unit are performed. The step (S1b) of recovering the refrigerant containing the odorant into the outdoor unit is what is known as pumping down.

[0084] As shown in FIG. 4 , the refrigerant discharge method for the refrigeration cycle apparatus according to the first embodiment first involves a step (S1b) of recovering the refrigerant containing odorant into the outdoor unit 1. In this step (S1b), the refrigerant and odorant in the closed refrigerant circuit 100 are recovered by pumping down into the condenser 4, the receiver, and other components of the outdoor unit 1. Specifically, the liquid pipe-side operating valve 17 is closed. Next, the compressor 3 is driven. This is preferably continued until the pressure in the indoor unit 2 and the gas pipe 10 becomes less than atmospheric pressure. This causes the odorant dissolved in the refrigeration oil present in the indoor unit 2 and the gas pipe 10 to evaporate. The evaporated, gaseous odorant moves into the outdoor unit 1.

[0085] Next, a step (S2b) of closing the outdoor unit is carried out. In this step (S2b), after the refrigerant and odorant have moved into the outdoor unit 1, a connection (not shown) connecting the outdoor unit 1 and the gas pipe 10 is closed. In this way, the refrigerant and odorant are trapped inside the outdoor unit 1.

[0086] Next, a step (S1a) of discharging the refrigerant containing the odorant from the refrigeration cycle apparatus and a step (S2a) of separating the odorant from the refrigerant are sequentially performed. The step (S1a) of discharging the refrigerant containing the odorant from the refrigerant from the refrigeration cycle apparatus and the step (S2a) of separating the odorant from the refrigerant are the same as the refrigerant discharging method in the first embodiment shown in Fig. 3. In this manner, the refrigerant and odorant trapped in the outdoor unit 1 can be discharged. As a result, the odor of the refrigerant is reduced when the refrigeration cycle apparatus is disassembled.

[0087] <Effects> In the above-described refrigerant discharge method, the refrigeration cycle apparatus has an outdoor unit. The refrigerant discharge method includes a step (S1b) of recovering the refrigerant containing the odorant into the outdoor unit, and a step (S2b) of closing the outdoor unit. By doing so, the odor of the refrigerant is reduced when the refrigeration cycle apparatus is disassembled.

[0088] Third Embodiment <Configuration of Processing Apparatus> Fig. 5 is a schematic diagram showing an example of a processing apparatus 13a according to the third embodiment. Fig. 6 is a schematic diagram of a separation unit 15a in the processing apparatus 13a according to the third embodiment.

[0089] The treatment device 13a shown in Figures 5 and 6 may be an exhaust device attached to the refrigeration cycle device as shown in Figure 1, and is a treatment device that treats the working fluid used in the refrigeration cycle device. The working fluid includes a refrigerant, a refrigerating machine oil, and an odorant.

[0090] The treatment device 13a is configured to maintain the temperature of the working fluid above the boiling point Tb1 of the refrigerant and below the boiling point Tb2 of the odorant. Specifically, as shown in FIG. 5 , the treatment device 13a includes a cooling unit 14a and a separation unit 15a. The working fluid treated by the treatment device 13a is supplied to the cooling unit 14a. The working fluid is cooled in the cooling unit 14a. By cooling the working fluid, the gaseous odorant mixed in the refrigerant is liquefied. As a result, the working fluid is configured to contain the gaseous refrigerant, the liquid odorant, and the refrigeration oil.

[0091] The working fluid cooled by the cooling unit 14a is supplied to the separation unit 15a. The working fluid supplied to the separation unit 15a is separated into a gaseous refrigerant and a liquid odorant in a separation container 16a. As shown in FIG. 5 , the cooling unit 14a and the separation unit 15a may be configured independently of each other, or the cooling unit 14a may include the separation unit 15a. In other words, the cooling unit 14a may cool the separation unit 15a. In this way, the cooling and separation of the refrigerant and the odorant can be performed simultaneously.

[0092] The odorant cooled by the cooling unit 14a is in a state of gas-liquid equilibrium. That is, an amount of odorant corresponding to the saturated vapor pressure of the odorant at the temperature during cooling is contained in the gaseous refrigerant (in the gas phase).

[0093] Here, a feature of the treatment device 13a according to the third embodiment is that the refrigerant and odorant are treated together with the refrigeration oil. The refrigerant and odorant are discharged together with the refrigeration oil, which is an example of a liquid, and thus the liquid odorant is contained in the refrigeration oil in the separation unit 15a. When the liquid odorant is contained in the refrigeration oil, a drop in the vapor pressure of the odorant occurs. The occurrence of a drop in the vapor pressure of the odorant means that the saturated vapor pressure of the odorant decreases, and the amount of odorant contained in the gas phase decreases. In other words, the occurrence of a drop in the vapor pressure of the odorant increases the amount of odorant separated from the gaseous refrigerant in the separation unit 15a, and the amount of odorant discharged outside the closed system together with the refrigerant can be reduced.

[0094] Here, the cooling unit 14a will be described in detail. In the cooling unit 14a, the working fluid (refrigerant, odorant, and refrigeration oil) is cooled to a temperature Tc. The temperature Tc is higher than the normal boiling point Tb1 of the refrigerant and lower than the normal boiling point Tb2 of the odorant. In this manner, the gaseous refrigerant is not liquefied in the cooling unit 14a, but the odorant is liquefied.

[0095] The temperature Tc may be higher than the standard melting point Tm2 of the odorant. In this way, the odorant does not solidify, and clogging within the treatment device 13a can be suppressed.

[0096] The cooling method in the cooling unit 14a is not particularly limited, and may be a cooling method by heat exchange or a cooling method by expansion. Specifically, the cooling method by heat exchange is a method of cooling the working fluid by heat exchange between the working fluid passing through the treatment device 13a and the outside. The cooling method by expansion is a method of cooling the working fluid by expanding the fluid passing through the treatment device 13a. The working fluid includes a refrigerant, an odorant, and a refrigerating machine oil.

[0097] The cooling method by heat exchange may be, for example, a method in which heat exchange is performed by bringing the processing device 13a into contact with a low-temperature medium. Heat exchange is performed by exposing at least a portion of the components constituting the processing device 13a to a medium such as a low-temperature gas or liquid. The low-temperature medium may be a substance inert to the components constituting the processing device 13a. This prevents a decrease in the strength of the processing device 13a and rapid deterioration.

[0098] When the cooling method in the cooling unit 14a is a heat exchange cooling method, at least a portion of the cooling unit 14a may be made of a material with high thermal conductivity. This allows for efficient cooling of the fluid passing through the processing device 13a. Examples of materials with high thermal conductivity include metals. Among metals, aluminum, iron, and copper have particularly high thermal conductivity and low reactivity with the refrigerant. Therefore, the material constituting at least a portion of the cooling unit 14a may be aluminum, iron, copper, or an alloy containing at least one of these as a main component.

[0099] When the cooling method in the cooling unit 14a is expansion cooling, the cooling unit 14a may be configured with, for example, an expansion valve, so that the working fluid that has flowed into the cooling unit 14a is supplied to the separation unit 15a in a state where the temperature has been reduced by the pressure reduction.

[0100] The working fluid (refrigerant, odorant, and refrigerating machine oil) cooled in this manner is supplied to the separation section 15a.

[0101] Next, the separation unit 15a will be described in detail. In order to prevent the odorant liquefied in the cooling unit 14a from being discharged from the treatment device 13a to the outside of the closed system, the liquid and gas are separated in the separation unit 15a, and only the gas is discharged to the outside of the closed system.

[0102] The separation method in the separation section 15a is not particularly limited, but may be any of a separation method that utilizes the density difference between gas and liquid, a separation method that utilizes surface tension, a separation method that utilizes centrifugal force, etc.

[0103] The separation method utilizing the density difference between gas and liquid is a method of separating liquid and gas by utilizing the fact that the density of the liquid is greater than the density of the gas, as shown in Fig. 6, for example. Specifically, a refrigerant, an odorant, and refrigerating machine oil are supplied to a separation container 16a. The liquid is stored in the lower part of the separation container 16a. The gas is discharged outside the closed system.

[0104] The separated liquid contains the odorant liquefied in the cooling section 14a and the refrigerating machine oil. The mixture of the refrigerating machine oil and the odorant in liquid form causes a vapor pressure drop of the odorant. The vapor pressure drop of the odorant in the separation section 15a reduces the amount of odorant present in the gas phase of the separation container 16a. In other words, compared to when no refrigerating machine oil is present in the separation section 15a, the amount of gaseous odorant discharged to the outside of the closed system together with the refrigerant is reduced, and the odor of the discharged gaseous refrigerant is reduced. As long as the odorant and the refrigerating machine oil are in contact with each other, a vapor pressure drop of the odorant occurs. Therefore, both the separation method utilizing surface tension and the separation method utilizing centrifugal force can achieve the effect of reducing the amount of odorant discharged by utilizing a vapor pressure drop.

[0105] The separation container 16a may include a liquid level indicator and a liquid discharge unit (not shown). The liquid level indicator displays the liquid level inside the separation container 16a. The liquid discharge unit enables the discharge of liquid stored inside the separation container 16a. The liquid stored inside the separation container 16a is discharged by opening and closing the liquid discharge unit. The liquid discharge unit may include, for example, a pipe connected to the bottom of the separation container 16a and an on-off valve installed on the pipe. The liquid indicator may include, for example, a sensor that detects the liquid level and a display unit that displays the detection result of the sensor.

[0106] When the liquid level in the separation container 16a rises above a predetermined height, the stored liquid may be discharged, thereby discharging the liquid odorant, thereby preventing the discharge of gaseous refrigerant with a strong odor.

[0107] The separation container 16a may also include a member (not shown) that can capture the odorant in the separation container 16a by adsorption or absorption. This further removes the odorant from the gas phase. As a result, the odor of the discharged gaseous refrigerant is reduced.

[0108] In a separation method that utilizes the density difference between gas and liquid, the configuration of the separation unit 15a does not have to be the configuration shown in Fig. 6. The separation unit 15a may be configured, for example, to include a space in which the diameter of a portion of the pipe that constitutes the treatment device 13a is enlarged, or may be configured to include a baffle-type oil separator.

[0109] In the treatment device 13a, a filter may be provided inside the separation unit 15a or in the piping downstream of the separation unit 15a. The filter prevents the liquid from being discharged outside the closed system and allows the gaseous refrigerant to pass through. This reduces the amount of odorant discharged outside the closed system and reduces the odor of the discharged gaseous refrigerant.

[0110] The filter is made of a material capable of absorbing odorants and refrigeration oil. The filter preferably has a highly breathable structure so as not to reduce the flow rate of the gaseous refrigerant. The filter may be made of, for example, a nonwoven fabric.

[0111] The gaseous refrigerant discharged from separation unit 15a is discharged either by recovery or by release into the atmosphere, depending on the refrigerant's global warming potential and legal regulations. The refrigerant is preferably recovered in a recovery container. However, if it is difficult to fill the recovery container with the refrigerant due to legal regulations or other reasons, the refrigerant is released into the atmosphere.

[0112] Furthermore, the refrigerant is a fluid whose normal boiling point Tb1 is lower than the normal boiling point Tb2 of the odorant. As a result, in the cooling unit 14a, the refrigerant and odorant are cooled to a temperature Tc between the normal boiling point Tb2 of the odorant and the normal boiling point Tb1 of the refrigerant, thereby selectively liquefying the odorant. As a result, only the gaseous refrigerant can be discharged outside the closed system. The refrigerant only needs to satisfy the above temperature relationship, and the material constituting the refrigerant may be either a halogenated hydrocarbon or a natural refrigerant, or a mixture thereof.

[0113] <Method of Treating Working Fluid> FIG. 7 is a flowchart of a method of treating a working fluid in the treatment device 13a according to the third embodiment. In the method of treating a working fluid in the treatment device 13a according to the third embodiment, first, a step (S1c) of preparing a working fluid is performed. In this step (S1c), for example, a working fluid used in a refrigeration cycle device is prepared. The working fluid includes a refrigerant, a refrigeration oil, and an odorant. The boiling point Tb2 of the odorant is higher than the boiling point Tb1 of the refrigerant. The refrigeration oil may be oxygenated oil.

[0114] Next, a step (S2c) of separating the odorant from the refrigerant is performed. In this step (S2c), the temperature of the working fluid is maintained above the boiling point Tb1 of the refrigerant and below the boiling point tb2 of the odorant, thereby separating the refrigerant from the odorant. Specifically, the prepared working fluid is cooled by the cooling unit 14a. In the cooling unit 14a, the temperature of the working fluid is cooled to a temperature Tc between the boiling point Tb2 of the odorant and the boiling point Tb1 of the refrigerant. In this way, the gaseous refrigerant does not liquefy, but the odorant liquefies. Note that the temperature Tc is above the standard melting point Tm2 of the odorant. Therefore, clogging of the discharge path 13 due to solidification of the odorant is suppressed. In particular, when the refrigeration oil is oxygenated oil, the odorant dissolves in the refrigeration oil.

[0115] The working fluid cooled by the cooling unit 14a is supplied to the separation unit 15a. The temperature of the working fluid supplied to the separation unit 15a is maintained above the boiling point Tb1 of the refrigerant and below the boiling point Tb2 of the odorant, so that the working fluid is separated into a gaseous refrigerant and a liquid odorant.

[0116] The gaseous refrigerant and the liquid odorant may be separated using a separation method that utilizes the density difference between the gas and the liquid. Specifically, the gaseous refrigerant and the liquid odorant are separated by using a separation container 16a as shown in FIG.

[0117] At this time, the working fluid contains refrigerating machine oil as well as the refrigerant and odorant. Therefore, the liquid odorant contains refrigerating machine oil. When the liquid odorant contains refrigerating machine oil, a vapor pressure drop of the odorant occurs. In other words, the vapor pressure drop of the odorant increases the amount of odorant separated in the separation section 15a. As a result, compared to when the refrigerating machine oil is not discharged, the amount of gaseous odorant discharged outside the closed system together with the refrigerant decreases, and the odor of the discharged gaseous refrigerant is reduced.

[0118] At this time, the temperature Tc may be higher than the pour point of the refrigerating machine oil, which can prevent clogging inside the treatment device 13a due to a decrease in the fluidity of the refrigerating machine oil.

[0119] In this way, the liquefied odorant and the gaseous refrigerant are separated, and the gaseous refrigerant is discharged outside the closed system.

[0120] <Effects> A method for treating a working fluid according to the present disclosure includes a step (S1c) of preparing a working fluid and a step (S2c) of separating an odorant from a refrigerant. The working fluid includes a refrigerant, a refrigeration oil, and an odorant. The odorant has a boiling point Tb1 higher than the boiling point Tb2 of the refrigerant. In the separating step (S1c), the temperature of the working fluid is maintained above the boiling point Tb1 of the refrigerant and below the boiling point Tb2 of the odorant.

[0121] In this way, the gaseous refrigerant and the liquid odorant can be separated, and the odor of the gaseous refrigerant can be suppressed.

[0122] According to the above-described method for treating a working fluid, the temperature in the separating step (S2c) is above the pour point of the refrigerating machine oil, which prevents clogging in the treatment device 13a due to a decrease in the fluidity of the refrigerating machine oil.

[0123] According to the above-described working fluid treatment method, the refrigeration oil is oxygen-containing oil. In this way, the refrigeration oil containing oxygen-containing oil can dissolve an odorant. Since the odorant dissolves in the refrigeration oil containing oxygen-containing oil, a vapor pressure drop of the odorant occurs. In other words, the vapor pressure drop of the odorant increases the amount of odorant that is liquefied. As a result, the odor of the discharged gaseous refrigerant can be reduced.

[0124] The treatment device 13a according to the present disclosure is a treatment device 13a that treats a working fluid. The working fluid includes a refrigerant, a refrigerating machine oil, and an odorant. The boiling point Tb1 of the odorant is higher than the boiling point Tb2 of the refrigerant. The treatment device 13a is configured to separate the gaseous refrigerant from the liquid odorant by cooling the temperature of the working fluid to above the boiling point Tb1 of the refrigerant and below the boiling point Tb2 of the odorant.

[0125] In this way, the gaseous refrigerant and the liquid odorant can be separated, and the odor of the gaseous refrigerant can be suppressed.

[0126] The processing device 13a according to the present disclosure includes a cooling unit 14a and a separation unit 15a. The cooling unit 14a cools a working fluid. The working fluid includes a refrigerant, refrigeration oil, and an odorant. In the cooled working fluid, the separation unit 15a separates the odorant from the refrigerant. The boiling point Tb1 of the odorant is higher than the boiling point Tb2 of the refrigerant. The cooling unit 14a cools the temperature of the working fluid to above the boiling point Tb1 of the refrigerant and below the boiling point Tb2 of the odorant. The separation unit 15a separates the gaseous refrigerant from the liquid odorant.

[0127] In this way, the gaseous refrigerant and the liquid odorant can be separated, and the odor of the gaseous refrigerant can be suppressed.

[0128] According to the treatment device 13a, the separation unit 15a separates the gaseous refrigerant from the liquid odorant by utilizing the density difference between the gas and the liquid.

[0129] In this way, the gaseous refrigerant and the liquid odorant can be separated, and the odor of the gaseous refrigerant can be suppressed.

[0130] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0131] 1 outdoor unit, 2 indoor unit, 3 compressor, 4 condenser, 5 outdoor blower, 6 expansion valve, 7 evaporator, 8 indoor blower, 9 liquid pipe, 10 gas pipe, 11 gas pipe side operation valve, 12 service port, 13 discharge path, 13a treatment device, 14, 14a cooling section, 15, 15a separation section, 16, 16a separation container, 17 liquid pipe side operation valve, 100 closed system refrigerant circuit, Tb1, Tb2 boiling point, Tm2 melting point, Tc temperature.

Claims

1. A method for treating a working fluid, comprising: a step of preparing a working fluid containing a refrigerant, a refrigeration oil, and an odorant; and a step of separating the odorant from the refrigerant, wherein the boiling point of the odorant is higher than the boiling point of the refrigerant, and during the separating step, the temperature of the working fluid is maintained above the boiling point of the refrigerant and below the boiling point of the odorant.

2. The method for treating a working fluid according to claim 1, wherein in the separating step, the temperature is above the pour point of the refrigerating machine oil.

3. The method for treating a working fluid according to claim 1 or 2, wherein the refrigeration oil is an oxygen-containing oil.

4. A treatment device for treating a working fluid containing a refrigerant, a refrigeration oil, and an odorant, wherein the boiling point of the odorant is higher than the boiling point of the refrigerant, and the treatment device is configured to maintain the temperature of the working fluid above the boiling point of the refrigerant and below the boiling point of the odorant.

5. A treatment device comprising: a cooling unit that cools a working fluid containing a refrigerant, refrigeration oil, and an odorant; and a separation unit that separates the odorant from the refrigerant in the cooled working fluid, wherein the boiling point of the odorant is higher than the boiling point of the refrigerant, the cooling unit cools the working fluid to a temperature above the boiling point of the refrigerant and below the boiling point of the odorant, and the separation unit separates the gaseous refrigerant and the liquid odorant.

6. The treatment device according to claim 5, wherein the separation section separates the refrigerant in a gaseous state from the odorant in a liquid state by utilizing the density difference between the gas and the liquid.

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