Refrigerant discharge method

Abstract

A refrigerant discharge method is obtained that improves the amount of odorant separated. The refrigerant discharge method 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.

Description

[Technical field]

[0001] The present disclosure relates to a refrigerant evacuation method. [Background technology]

[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. 2021 / 166028). When discharging the refrigerant from the refrigeration cycle device, the odorant alone can be liquefied and separated from the refrigerant by utilizing the difference in boiling points between the refrigerant and the odorant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 166028 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since not all of the odorant contained in the refrigerant is liquefied and some of the odorant remains in the gas phase, there is room for improvement in separating the odorant from the refrigerant.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a refrigerant discharge method in which an amount of odorant separated is improved. [Means for solving the problem]

[0006] A refrigerant discharging method according to the present disclosure includes a step of discharging a refrigerant containing an odorant from a refrigeration cycle device, and a step of separating the odorant from the refrigerant after the discharging step. The boiling point of the odorant is higher than the boiling point of the refrigerant. In the discharging step, the refrigerant is discharged together with refrigeration oil. In the separating step, the refrigerant containing the odorant is cooled to a temperature between the boiling point of the odorant and the boiling point of the refrigerant. The temperature is above the melting point of the odorant. Effect of the Invention

[0007] According to the above, it is possible to obtain a refrigerant discharging method in which an increased amount of odorant is separated. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an example of a refrigeration cycle device (closed refrigerant circuit) according to a first embodiment. [Diagram 2] 3 is a schematic diagram of a separation section in the refrigeration cycle device according to the first embodiment. FIG. [Diagram 3] 4 is a flowchart of a refrigerant discharging method in the refrigerant cycle apparatus according to the first embodiment. [Figure 4] 10 is a flowchart of a refrigerant discharging method in the refrigerant cycle apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described. Note that unless otherwise specified, the same or corresponding parts in the following drawings are given the same reference numerals, and the description thereof will not be repeated.

[0010] Embodiment 1 <Configuration of refrigeration cycle device (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 section 15 in the refrigeration cycle apparatus according to embodiment 1.

[0011] The refrigeration cycle device is, for example, a refrigeration cycle device for air conditioning, and as shown in Fig. 1, mainly includes 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.

[0012] 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.

[0013] 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. With such a configuration of the refrigeration cycle device, a closed refrigerant circuit 100 is formed. The refrigerant and odorant circulate within the closed refrigerant circuit 100 via the liquid pipe 9 and the gas pipe 10.

[0014] The compressor 3 compresses the refrigerant and odorant that have become gaseous 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 reduces the pressure of the high-pressure liquid state or the two-phase gas-liquid state refrigerant and odorant. The evaporator 7 heats the reduced pressure refrigerant and odorant to turn them into a low-pressure gaseous state. The compressor 3 draws in the refrigerant and odorant that have become low-pressure gaseous by the evaporator 7 and compresses them again.

[0015] 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. By providing the accumulator, the suction muffler, and the receiver, a large amount of liquid refrigerant is prevented from flowing into the compressor 3. As a result, it is possible to prevent the refrigeration oil from being excessively diluted and the lubricity of the sliding parts of the compressor 3 from deteriorating.

[0016] Refrigeration oil is contained inside the compressor 3. The refrigeration oil maintains the lubrication of the sliding parts of the compressor 3. The refrigeration 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 refrigeration oil circulates in the closed refrigerant circuit 100 together with the refrigerant and odorant.

[0017] The outdoor blower 5 sends air to the condenser 4. The outdoor blower 5 is provided so that the refrigerant flowing through the condenser 4 exchanges heat with the air, facilitating the absorption or release of heat. The indoor blower 8 sends air to the evaporator 7. The indoor blower 8 is provided so that the refrigerant flowing through the evaporator 7 exchanges heat with the air, facilitating the absorption or release of heat.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] For example, a switching mechanism (not shown) may be provided for the outdoor unit 1 as described above. 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.

[0022] 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.

[0023] The use of the refrigeration cycle apparatus according to the first embodiment is not limited to air conditioning, but may also be for freezing, refrigeration, or hot water supply.

[0024] 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 filled into the closed refrigerant circuit 100 or the refrigerant can be discharged from the closed refrigerant circuit 100.

[0025] 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 so that the refrigerant and odorant are discharged outside the closed system. At this time, the refrigerant and odorant pass through the service port 12 and are supplied to the discharge device.

[0026] When the refrigerant in the closed refrigerant circuit 100 is discharged outside 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 section 14 and a separation section 15. The refrigerant and odorant that have passed through the service port 12 are supplied to the cooling section 14. The refrigerant and odorant are cooled in the cooling section 14.

[0027] The refrigerant and odorant cooled in 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 in 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 the odorant can be performed simultaneously.

[0028] The odorant cooled by the cooling unit 14 is in a state of gas-liquid equilibrium. That is, an amount of odorant equivalent 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 outside the closed system, the odorant remains in the gas phase, and a portion of the odorant is discharged together with the refrigerant.

[0029] Here, the refrigerant discharge method according to the first embodiment is characterized in 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 refrigerating machine oil contains liquid odorant in separation section 15. When liquid odorant is contained in the refrigerating machine oil, a vapor pressure drop of the odorant occurs. The occurrence of a vapor pressure drop 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 vapor pressure drop of the odorant increases the amount of odorant separated from the gaseous refrigerant in separation section 15, and the amount of odorant discharged together with the refrigerant to the outside of the closed system can be reduced.

[0030] Here, the cooling unit 14 will be specifically described. In the cooling unit 14, the refrigerant, the odorant, and the 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.

[0031] The temperature Tc is preferably higher than the standard melting point Tm2 of the odorant, so that the odorant does not solidify and the clogging of the discharge path 13 can be prevented.

[0032] 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. The cooling method by heat exchange is specifically 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 fluids referred to here are refrigerants, odorants, and refrigeration oils.

[0033] The cooling method by heat exchange may be, for example, a method in which heat exchange is performed by contacting the exhaust path 13 with a low-temperature medium. Heat exchange is performed by exposing at least a part of the member 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 member constituting the exhaust path 13. In this way, it is possible to prevent the strength of the exhaust path 13 from decreasing and deterioration in a short period of time.

[0034] When the cooling method in the cooling unit 14 is a cooling method by heat exchange, it is preferable that at least a part of the cooling unit 14 is made of a material with high thermal conductivity. In this way, the fluid passing through the discharge path 13 can be efficiently cooled. An example of a material with high thermal conductivity is a metal. In particular, among metals, aluminum, iron, copper, and the like have high thermal conductivity and low reactivity with the refrigerant. Therefore, it is preferable that the material constituting at least a part of the cooling unit 14 is aluminum, iron, copper, or an alloy containing at least one of them as a main component.

[0035] In the cooling method by heat exchange, heat exchange may be performed using a refrigeration cycle device (second refrigeration cycle device) different 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, it is preferable that the members constituting the discharge path 13 and the members constituting the evaporator of the second refrigeration cycle device are made of materials mainly composed of the same type of metal. In this way, galvanic corrosion does not occur in the members constituting the discharge path 13 and the members constituting the evaporator of the second refrigeration cycle device.

[0036] The refrigerant, odorant, and refrigeration oil cooled in this manner are supplied to the separation section 15.

[0037] Next, a specific description will be given of the separation section 15. In order to prevent the odorant liquefied in the cooling section 14 from being discharged from the discharge path 13 to the outside of the closed system, the liquid and the gas are separated in the separation section 15, and only the gas is discharged to the outside of the closed system.

[0038] The separation method in separation section 15 is not particularly limited, but may be any of a separation method utilizing the density difference between gas and liquid, a separation method utilizing surface tension, a separation method utilizing centrifugal force, etc.

[0039] 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 liquid is greater than the density of gas, for example, as shown in Fig. 2. Specifically, a refrigerant, an odorant, and a refrigeration 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.

[0040] The separated liquid contains the odorant liquefied in the cooling section 14 and the refrigeration oil. The mixture of the refrigeration oil and the odorant as liquids causes a vapor pressure drop of the odorant. The vapor pressure drop of the odorant occurs in the separation section 15, and the amount of odorant present in the gas phase of the separation container 16 decreases. In other words, compared to the case where there is no refrigeration oil in the separation section 15, the amount of gaseous odorant discharged to the outside of the closed system together with the refrigerant decreases, and the odor of the discharged gaseous refrigerant decreases. As long as the odorant and the refrigeration oil are in contact with each other, a vapor pressure drop of the odorant occurs. Therefore, in both the separation method using surface tension and the separation method using centrifugal force, the effect of reducing the amount of odorant discharged using a vapor pressure drop can be obtained.

[0041] The separation container 16 may include a liquid level indicator and a liquid discharge part (not shown). The liquid level indicator displays the height of the liquid level inside the separation container 16. The liquid discharge part 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.

[0042] When the liquid level in the separation container 16 rises to a predetermined height or higher, the stored liquid may be discharged. This allows the liquid odorant to be discharged. As a result, it is possible to prevent the discharge of gaseous refrigerant having a strong odor.

[0043] 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.

[0044] In addition, in a separation method that utilizes the density difference between gas and liquid, the configuration of separation section 15 does not have to be the configuration shown in Fig. 2. Separation section 15 may be configured to include a space in which the diameter of a part of the pipe that constitutes discharge path 13 is enlarged, or may be configured to include a baffle-type oil separator, for example.

[0045] The amount of refrigeration oil discharged may be increased by rapidly opening the gas pipe side operation valve 11 to the outside of the closed system. Specifically, when the gas pipe side operation valve 11 is rapidly opened, the pressure in the closed refrigerant circuit 100 decreases, and the refrigerant dissolved in the refrigeration oil in the compressor 3 rapidly evaporates. The evaporation of the refrigerant causes the refrigeration oil to foam. That is, the refrigerant contained in the refrigeration oil vaporizes, and the apparent volume of the refrigeration oil increases. As a result, the oil level of the refrigeration oil rises, and the amount of refrigeration oil flowing out to the pipes forming the closed refrigerant circuit 100 increases. As a result, the amount of refrigeration oil supplied to the discharge path 13 increases. In this way, the effect of separating the odorant from the gaseous refrigerant by the refrigeration oil can be improved.

[0046] Here, when opening the gas pipe side operation valve 11, it is preferable to open the gas pipe side operation valve 11 rapidly so that the flow rate of the refrigerant discharged immediately after opening the gas pipe side operation valve 11 is greater than the evaporation amount 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 amount 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.

[0047] In addition, the refrigeration oil in the compressor 3 may be heated before or while the gas pipe side operation valve 11 is opened. By heating the refrigeration oil in the compressor 3, the refrigerant and odorant dissolved in the refrigeration oil evaporate. As a result, the refrigeration oil foams. That is, the oil level of the refrigeration oil rises, and the amount of refrigeration oil supplied to the discharge path 13 increases. In this way, the effect of separating the odorant from the gaseous refrigerant by the refrigeration oil can be improved.

[0048] In addition, by performing the rapid opening of the gas pipe side operation valve 11 and the heating inside the compressor 3 in combination, the amount of refrigeration oil supplied to the discharge path 13 is further increased.

[0049] 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.

[0050] The material constituting the filter is a material capable of absorbing odorant and refrigeration oil. The filter is preferably structured to have excellent breathability so as not to reduce the flow rate of the gaseous refrigerant. The material constituting such a filter may be, for example, a nonwoven fabric.

[0051] The gaseous refrigerant discharged from separation section 15 is discharged either by recovery or by release into the atmosphere, depending on the global warming potential of the refrigerant 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.

[0052] 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°, the normal boiling point Tb1 of the refrigerant is preferably lower than 15°. This allows the refrigerant in the closed refrigerant circuit 100 to be discharged to the outside by vapor pressure. In other words, when discharging the refrigerant, there is no need to suck the refrigerant with a pump or the like.

[0053] Furthermore, the refrigerant is a fluid whose normal boiling point Tb1 is lower than the normal boiling point Tb2 of the odorant. In this way, the refrigerant and the odorant are cooled in the cooling unit 14 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 may be a mixture thereof.

[0054] 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), ... 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.

[0055] In particular, as a refrigerant with a small global warming potential, it is more preferable that the refrigerant used is 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).

[0056] 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. Hydrocarbons are refrigerants that are 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 small global warming potential and are therefore suitable as refrigerants for use in refrigeration cycle devices.

[0057] It is preferable that the odorant has a unique odor. Since the odorant has a unique odor, the refrigerant mixed with the odorant can be detected by the sense of smell. Materials constituting the odorant include, for example, mercaptans, sulfides, thiophenes, cyclohexene, acrylic acid 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. The thiophenes include, for example, tetrahydrothiophene. These odorants may be used alone or in combination of two or more. In addition, the materials constituting the odorant may contain compounds having a specific odor other than the above materials.

[0058] In addition, the odorant is a material having a standard boiling point Tb2 higher than the standard boiling point Tb1 of the refrigerant. In this way, the refrigerant and the odorant are cooled in the cooling unit 14 to a temperature Tc between the standard boiling point Tb2 of the odorant and the standard boiling point Tb1 of the refrigerant, so that the odorant can be selectively liquefied. For example, when R-290 is used as the refrigerant, the standard boiling point Tb1 of R-290 is -42°C. Therefore, an odorant having a standard boiling point Tb2 higher than -42°C is used as the odorant. For example, tetrahydrothiophene having a standard boiling point Tb2 of 121°C or cyclohexene having a standard 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, it is sufficient that the standard boiling points Tb2 of all of the odorants are higher than the standard boiling point Tb1 of the refrigerant.

[0059] In the case where the refrigerant is a non-azeotropic mixed refrigerant, it is preferable that the normal boiling point Tb2 of the odorant is higher than the boiling point Tb1 of the refrigerant under atmospheric pressure. In this way, the refrigerant is not liquefied in the cooling unit 14, and the odorant can be selectively liquefied. For example, in the case where R-454B is used as the refrigerant, the dew point of R-454B under atmospheric pressure is −50.9° C., and the boiling point Tb1 under atmospheric pressure is −50.0° C. In this case, it is preferable to use an odorant having a normal boiling point Tb2 higher than −50.0° C. as the odorant. Note that R-454B is a mixed refrigerant of R-32 and R-1234y, and the mass ratio of R-32 and R-1234y (=R-32 / R-1234yf) is 68.9 mass% / 31.1 mass%.

[0060] The refrigeration oil includes a base oil. The base oil includes at least one of an oxygen-containing oil and a hydrocarbon oil. The oxygen-containing oil is, for example, a polyalkylene glycol, a polyol ester, a polyvinyl ether, etc. The hydrocarbon oil is, for example, a polyalphaolefin, an alkylbenzene, an alkylnaphthalene, a mineral oil, etc.

[0061] The lubrication of the sliding parts of the compressor 3 depends greatly on the kinetic viscosity of the base oil contained in the refrigeration oil. The material constituting the base oil is preferably a material having a kinetic viscosity higher than that of the refrigerant. The kinetic 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 material constituting the base oil, the kinetic viscosity of the base oil can be made to fall within the above range. When the base oil has a kinetic viscosity higher than that of the refrigerant, the cooling efficiency of the refrigeration cycle device is not significantly reduced, and the lubricity of the sliding parts in the compressor 3 is maintained.

[0062] The base oil is preferably an oxygen-containing oil. Oxygen-containing oil has high polarity. Therefore, oxygen-containing oil can dissolve compounds having polarity. Here, the odorant exemplified as a material constituting the odorant has any one of a nitrogen atom, an oxygen atom, a sulfur atom, and a carbon-carbon double bond in the chemical structure. In other words, the odorant described above is a compound having polarity due to the bias of electric charge. Therefore, refrigeration oil containing oxygen-containing oil can dissolve the odorant. Since the odorant dissolves in refrigeration oil containing oxygen-containing oil, a vapor pressure drop of the odorant occurs. In other words, the amount of the odorant separated in the separation unit 15 is improved by the vapor pressure drop of the odorant. As a result, the odor of the gaseous refrigerant gas discharged can be reduced.

[0063] The pour point of the refrigeration oil is preferably lower than the temperature Tc of the refrigerant, odorant, and refrigeration oil in the cooling unit 14. When the pour point of the refrigeration oil is lower than the temperature Tc in the cooling unit 14, clogging of the discharge path 13 due to a decrease in the fluidity of the refrigeration oil can be prevented.

[0064] The refrigeration oil may contain, as an in-oil additive, an antioxidant, an acid scavenger, an extreme pressure agent (anti-wear agent), an oxygen scavenger, a fluorescent agent, a colorant, etc. However, in order to prevent the clogging of the discharge path 13 by the in-oil additives, it is preferable that these in-oil additives do not precipitate when the refrigeration oil is cooled in the cooling section 14.

[0065] <Refrigerant discharge method> FIG. 3 is a flow chart of a refrigerant discharge method in the refrigeration cycle apparatus according to the first embodiment. In the refrigerant discharge method in the refrigeration cycle apparatus according to the first embodiment, a step (S1a) of discharging the refrigerant is first carried out. 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 operation valve 11 is opened so that the refrigerant and the odorant in the closed refrigeration circuit 100 are discharged to the discharge device. At this time, the refrigerant and the odorant are discharged together with the refrigeration oil. Note that, in the refrigerant and the 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 an oxygen-containing oil.

[0066] When the gas pipe side operation valve 11 is opened, the gas pipe side operation valve 11 is opened rapidly so that the flow rate of the refrigerant discharged immediately after the gas pipe side operation valve 11 is opened is greater than the evaporation amount of the refrigerant. Specifically, the gas pipe side operation valve 11 is opened rapidly so that the flow rate of the refrigerant passing through the discharge path 13 is greater than the evaporation amount of the refrigerant contained in the liquid phase (including the refrigerant oil) in the closed refrigerant circuit 100 immediately after the gas pipe side operation valve 11 is opened. In addition, the refrigerant oil in the compressor 3 may be heated before or during the opening of the gas pipe side operation valve 11.

[0067] Next, a step (S2a) of separating the odorant from the refrigerant is performed. In this step (S2a), the refrigerant, the odorant, and the refrigeration oil are cooled to separate the refrigerant and the odorant. The refrigerant, the odorant, and the refrigeration oil supplied to the exhaust 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, and the odorant liquefies. The temperature Tc is higher than the standard melting point Tm2 of the odorant. Therefore, clogging of the exhaust path 13 due to solidification of the odorant is suppressed. In particular, when the refrigeration oil is an oxygen-containing oil, the odorant dissolves in the refrigeration oil.

[0068] 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 liquid odorant. When the refrigerating machine oil contains liquid odorant, a vapor pressure drop of the odorant occurs. In other words, the amount of odorant separated in the exhaust device increases due to the vapor pressure drop of the odorant. As a result, compared to the case where 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 decreases.

[0069] At this time, it is preferable that the temperature Tc is higher than 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.

[0070] In this manner, the odorant is separated from the gaseous refrigerant, and the gaseous refrigerant is discharged outside the closed system.

[0071] <Action and effect> The refrigerant discharging 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.

[0072] In this way, a vapor pressure drop of the odorant occurs. In other words, the amount of odorant separated by the exhaust device increases due to the vapor pressure drop of the odorant. As a result, compared to the case where the refrigeration oil is not discharged, the amount of gaseous odorant discharged to the outside of the closed system together with the refrigerant decreases, and the odor of the discharged gaseous refrigerant is reduced.

[0073] In the above-described refrigerant discharge method, in the separation step (S2a), the temperature Tc is higher than the pour point of the refrigerating machine oil. In this way, since the pour point of the refrigerating machine oil is lower than the temperature Tc, clogging of the discharge path 13 due to a decrease in the fluidity of the refrigerating machine oil can be prevented.

[0074] In the above refrigerant discharge method, the refrigerating machine oil is an oxygen-containing oil. In this way, the refrigerating machine oil containing the oxygen-containing oil can dissolve the odorant. Since the odorant dissolves in the refrigerating machine oil containing the oxygen-containing oil, a vapor pressure drop of the odorant occurs. In other words, the amount of odorant that is liquefied increases due to the vapor pressure drop of the odorant. As a result, the odor of the discharged gaseous refrigerant gas can be reduced.

[0075] In the above-described refrigerant discharge method, the refrigeration cycle device includes a compressor 3. In a discharging step (S1a), the refrigerating machine oil in the compressor 3 is foamed. In this way, the oil level of the refrigerating machine oil rises, and the amount of the refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0076] In the above-mentioned refrigerant discharge method, the refrigeration cycle device 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 the refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0077] In the above-mentioned 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 immediately after the gas pipe side operation valve 11 is opened is greater than the amount of evaporation of the refrigerant. In this way, the oil level of the refrigerating machine oil rises, and the amount of the 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, 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 the refrigerating machine oil supplied to the discharge path 13 increases. As a result, the amount of odorant separated from the gaseous refrigerant increases.

[0079] Embodiment 2 <Refrigerant discharge method> Fig. 4 is a flowchart of a refrigerant discharge method in a refrigerant cycle apparatus according to embodiment 2. Fig. 4 corresponds to Fig. 3. The refrigerant discharge method in the refrigerant cycle apparatus shown in Fig. 4 basically has the same configuration as the refrigerant discharge method in the refrigerant cycle apparatus shown in Fig. 3, but differs in that pump-down is performed before discharging the refrigerant.

[0080] When the refrigerant is discharged outside the closed system by the refrigerant discharge method in the refrigeration cycle apparatus according to the first embodiment, the vapor pressure in the closed refrigerant circuit 100 is in equilibrium with the atmospheric pressure. When the vapor pressure in the closed refrigerant circuit 100 is in equilibrium with the atmospheric pressure, the refrigerant and odorant in the closed refrigerant circuit 100 are difficult to discharge. As a result, the odor of the odorant remains in the closed refrigerant circuit 100. With the odor of the odorant remaining in the closed refrigerant circuit 100, the refrigeration cycle apparatus is dismantled for relocation, repair, or the like. At that time, the odor of the odorant is discharged outside the closed system.

[0081] Here, in order to further remove odorant remaining in the closed refrigerant circuit 100, pump-down may be performed before discharging the refrigerant from the refrigeration cycle device. Specifically, before discharging the refrigerant, a step (S1b) of recovering the refrigerant containing the odorant in the outdoor unit and a step (S2b) of closing the outdoor unit are performed. The step (S1b) of recovering the refrigerant containing the odorant in the outdoor unit is what is called pump-down.

[0082] As shown in FIG. 4, in the refrigerant discharge method in the refrigeration cycle device according to the first embodiment, first, a step (S1b) is carried out to recover the refrigerant containing the odorant in the outdoor unit 1. In this step (S1b), the refrigerant and the odorant in the closed refrigerant circuit 100 are recovered in the condenser 4 and the receiver constituting the outdoor unit 1 by pumping down. Specifically, the liquid pipe side operation valve 17 is closed. Next, the compressor 3 is driven. At this time, it is preferable to carry out this process until the pressure in the indoor unit 2 and the gas pipe 10 becomes a value below atmospheric pressure. In this way, the odorant dissolved in the refrigeration oil present in the indoor unit 2 and the gas pipe 10 evaporates. The evaporated odorant in a gaseous state moves into the outdoor unit 1.

[0083] Next, a step (S2b) of closing the outdoor unit is carried out. In this step (S2b), after the refrigerant and odorant have moved to the outdoor unit 1, a connection part (not shown) that connects 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.

[0084] Next, a step (S1a) of discharging the refrigerant containing the odorant from the refrigerant cycle device 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 cycle device 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 device is disassembled.

[0085] <Action and effect> In the above-mentioned refrigerant discharge method, the refrigeration cycle device has an outdoor unit. The refrigerant discharge method includes a step (S1b) of recovering the refrigerant containing the odorant in the outdoor unit, and a step (S2b) of closing the outdoor unit. In this way, the odor of the refrigerant is reduced when the refrigeration cycle device is disassembled.

[0086] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Unless inconsistent, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0087] 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 control valve, 12 service port, 13 exhaust path, 14 cooling section, 15 separation section, 16 separation vessel, 17 liquid pipe side control valve, 100 closed refrigerant circuit, Tb1, Tb2 boiling point, Tm2 melting point, Tc temperature.

Claims

1. A step of discharging a refrigerant containing an odorant from a refrigeration cycle device, and a step of separating the odorant from the refrigerant after the discharging step, wherein the boiling point of the odorant is higher than the boiling point of the refrigerant, in the discharging step, the refrigerant is discharged together with refrigeration oil, in the separating step, the refrigerant containing the odorant is cooled to a temperature between the boiling point of the odorant and the boiling point of the refrigerant, wherein the temperature exceeds the melting point of the odorant, a refrigerant discharging method.

2. In the separating step, the temperature exceeds the pour point of the refrigeration oil, the refrigerant discharging method according to claim 1.

3. The refrigeration oil is oxygen-containing oil, the refrigerant discharging method according to claim 1.

4. The refrigeration oil is oxygen-containing oil, the refrigerant discharging method according to claim 2.

5. The refrigeration cycle device has an outdoor unit, a step of recovering the refrigerant containing the odorant into the outdoor unit, and a step of closing the outdoor unit, the refrigerant discharging method according to claim 1.

6. The refrigeration cycle device has an outdoor unit, a step of recovering the refrigerant containing the odorant into the outdoor unit, and a step of closing the outdoor unit, the refrigerant discharging method according to claim 2.

7. The refrigeration cycle device has an outdoor unit, a step of recovering the refrigerant containing the odorant into the outdoor unit, and a step of closing the outdoor unit, the refrigerant discharging method according to claim 3.

8. The refrigeration cycle device has an outdoor unit, a step of recovering the refrigerant containing the odorant into the outdoor unit, and a step of closing the outdoor unit, the refrigerant discharging method according to claim 4.

9. The refrigeration cycle device includes a compressor, in the discharging step, foaming the refrigeration oil in the compressor, the refrigerant discharging method according to any one of claims 1 to 8.

10. The refrigeration cycle device is connected to a discharging device via a gas pipe side operation valve, in the discharging step, rapidly opening the gas pipe side operation valve to foam the refrigeration oil in the compressor, the refrigerant discharging method according to claim 9.

11. In the discharging step, rapidly opening the gas pipe side operation valve so that the flow rate of the discharged refrigerant immediately after opening the gas pipe side operation valve is greater than the evaporation amount of the refrigerant, the refrigerant discharging method according to claim 10.

12. In the discharging step, The refrigerant discharge method according to claim 9, wherein the refrigerant oil in the compressor is heated to foam the refrigerant oil.

13. In the discharging step, The refrigerant discharge method according to claim 10, wherein the refrigerant oil in the compressor is heated to foam the refrigerant oil.

14. In the discharging step, The refrigerant discharge method according to claim 11, wherein the refrigerant oil in the compressor is heated to foam the refrigerant oil.

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