Refrigeration cycle device

Abstract

This refrigeration cycle device comprises a refrigerant circuit including a compressor. The refrigerant circuit contains a refrigerant and an odorant, and the compressor is filled with refrigerating machine oil. The oil circulation rate of the refrigerant circuit is at least 0.01 wt%.

Description

Refrigeration cycle equipment

[0001] This disclosure relates to a refrigeration cycle system.

[0002] Patent Document 1 discloses a refrigeration cycle device. This refrigeration cycle device includes a refrigerant circuit through which a refrigerant circulates. The refrigerant contains a sulfur-based odorant. With this configuration, since the refrigerant leaking from the refrigerant circuit contains a sulfur-based odorant, the refrigerant leak can be detected by smell.

[0003] International Publication No. 2021 / 166028

[0004] However, in the above-mentioned refrigeration cycle system, sulfur-based odorants can dissolve in the refrigerant oil, reducing the amount of sulfur-based odorant circulating in the refrigerant circuit. This presents a challenge in that it can be difficult to detect refrigerant leaks using human olfaction.

[0005] This disclosure is made to solve the problems described above and aims to provide a refrigeration cycle device that can more reliably detect refrigerant leaks using human olfaction.

[0006] The refrigeration cycle device according to this disclosure comprises a refrigerant circuit including a compressor, the refrigerant circuit is filled with a refrigerant and an odorant, the compressor is filled with refrigerant oil, and the oil circulation rate of the refrigerant circuit is 0.01 wt% or more.

[0007] According to this disclosure, refrigerant leaks can be more reliably detected by a person's sense of smell.

[0008] This is a refrigerant circuit diagram showing the schematic configuration of the refrigeration cycle device according to Embodiment 1. This is a cross-sectional view showing the configuration of the compressor of the refrigeration cycle device according to Embodiment 1. This is a graph showing the temperature dependence of the odorant concentration in the released refrigerant in Embodiment 1. This is a graph showing the refrigerant mass fraction dependence of the odorant concentration in the released refrigerant in Embodiment 1. This is a graph showing the odorant composition dependence of the odorant concentration in the released refrigerant in Embodiment 1. This is a graph showing the relationship between the oil circulation rate and the odor index equivalent value in the refrigeration cycle device according to Embodiment 1. This is a graph showing the relationship between the oil circulation rate and the odor index equivalent value in the refrigeration cycle device according to Embodiment 1. This is a graph showing the relationship between the oil circulation rate and the performance influence in the refrigeration cycle device according to Embodiment 2. This is a graph showing the relationship between the oil circulation rate and the mass ratio of refrigerant to refrigerant oil in the refrigeration cycle device according to Embodiment 3.

[0009] The embodiments relating to this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below, and can be modified in various ways without departing from the spirit of this disclosure. Furthermore, this disclosure includes all possible combinations of the configurations shown in each of the embodiments described below. In particular, the combinations of components are not limited to the combinations in each embodiment, and components described in one embodiment can be applied to another embodiment. In addition, in the following description, terms indicating direction (e.g., "up," "down," "right," "left," "front," "back," etc.) may be used as appropriate to facilitate understanding, but these are for illustrative purposes only and do not limit this disclosure. Also, in each drawing, components with the same reference numerals are the same or equivalent, and this is common throughout the entire specification. Note that the relative dimensions or shapes of each component in each drawing may differ from those of the actual components.

[0010] Embodiment 1. A refrigeration cycle device according to Embodiment 1 will be described. Figure 1 is a refrigerant circuit diagram showing the schematic configuration of the refrigeration cycle device according to this embodiment. The refrigeration cycle device of this embodiment is used in refrigeration and air conditioning equipment such as air conditioners and refrigerators. As shown in Figure 1, the refrigeration cycle device 200 has a refrigerant circuit 201. The refrigerant circuit 201 has a compressor 100, a four-way valve 103, an outdoor heat exchanger 104, a throttling device 105 such as an electronic expansion valve, and an indoor heat exchanger 106. The compressor 100, the four-way valve 103, the outdoor heat exchanger 104, the throttling device 105, and the indoor heat exchanger 106 are connected in a ring shape via refrigerant piping. The refrigerant circuit 201 is sealed with a refrigerant and an odorant. The refrigerant circulates through the refrigerant circuit 201 together with the odorant. Details of the refrigerant and odorant will be described later.

[0011] The four-way valve 103 is configured to switch the flow of refrigerant in the refrigerant circuit 201. The four-way valve 103 is connected to the discharge side of the compressor 100 in the refrigerant circuit 201. Generally, in refrigeration and air conditioning systems such as air conditioners, the indoor heat exchanger 106 is mounted on the indoor unit installed inside a room. The compressor 100, four-way valve 103, outdoor heat exchanger 104, and throttling device 105 are mounted on the outdoor unit installed outside.

[0012] Figure 2 is a cross-sectional view showing the configuration of a compressor in a refrigeration cycle device according to this embodiment. In this embodiment, a single-cylinder rotary compressor is exemplified as the compressor. As shown in Figure 2, the compressor 100 includes a compression mechanism 20 for compressing refrigerant gas, an electric motor 30 for driving the compression mechanism 20, and a sealed container 10 that houses the compression mechanism 20 and the electric motor 30. The sealed container 10 includes a cylindrical body 11, an upper lid 12 that closes the upper opening of the body 11, and a lower lid 13 that closes the lower opening of the body 11. A discharge pipe 102 is provided in the upper lid 12. The compression mechanism 20 is located in the lower part of the sealed container 10. The electric motor 30 is located above the compression mechanism 20 within the sealed container 10.

[0013] The electric motor 30 has a stator 32 and a rotor 31. The stator 32 is fixed to the inner circumferential surface of the sealed container 10. The rotor 31 is provided on the inner circumferential side of the stator 32. The inner circumferential surface of the stator 32 and the outer circumferential surface of the rotor 31 face each other with an air gap in between. A rotating shaft 21 is fixed to the center of the rotor 31.

[0014] The compression mechanism 20 is connected to the rotor 31 by a rotating shaft 21. The rotational force of the electric motor 30 is transmitted to the compression mechanism 20 via the rotating shaft 21. The compression mechanism 20 compresses the refrigerant gas using the transmitted rotational force and discharges it into the sealed container 10. The inside of the sealed container 10 is filled with compressed high-temperature, high-pressure refrigerant gas.

[0015] A refrigerant oil 14 for lubricating the compression mechanism 20 is stored at the bottom of the sealed container 10. In Figure 2, the refrigerant oil 14 is hatched. An oil pump (not shown) is provided below the rotating shaft 21. As the rotating shaft 21 rotates, the oil pump draws up the refrigerant oil from the bottom of the sealed container 10 and supplies it to the sliding parts of the compression mechanism 20. This ensures the mechanical lubrication of the compression mechanism 20. Details of the refrigerant oil will be described later.

[0016] The rotating shaft 21 has a main shaft portion 21a, an eccentric shaft portion 21b, and a sub-shaft portion 21c. The main shaft portion 21a, the eccentric shaft portion 21b, and the sub-shaft portion 21c are arranged in this order along the axial direction of the rotating shaft 21. The rotor 31 of the electric motor 30 is fixed to the main shaft portion 21a by shrink fitting or press fitting. A cylindrical rolling piston 22 is slidably fitted to the eccentric shaft portion 21b.

[0017] The compression mechanism 20 includes a cylinder 23, a rolling piston 22, an upper bearing 24, a lower bearing 25, and vanes (not shown). The cylinder 23 is formed in a hollow cylindrical shape. Inside the cylinder 23 is a cylindrical space, i.e., a cylinder chamber 23a, with both ends in the axial direction open.

[0018] The cylinder chamber 23a houses an eccentric shaft 21b, a rolling piston 22, and vanes. The eccentric shaft 21b performs eccentric rotational motion within the cylinder chamber 23a as the rotation of the rotating shaft 21 occurs. The rolling piston 22 is fitted onto the outer circumference of the eccentric shaft 21b. The space formed by the inner circumferential surface of the cylinder 23 and the outer circumferential surface of the rolling piston 22 is partitioned by vanes.

[0019] The upper bearing 24 rotatably supports the main shaft portion 21a of the rotating shaft 21. The upper bearing 24 also serves as an end plate that closes one of the axial openings of the cylinder chamber 23a. The upper bearing 24 has an almost inverted T-shape when viewed from the side.

[0020] The lower bearing 25 rotatably supports the sub-shaft portion 21c of the rotating shaft 21. The lower bearing 25 also serves as an end plate that closes the other axial opening of the cylinder chamber 23a. The lower bearing 25 is approximately T-shaped when viewed from the side.

[0021] The cylinder 23 is provided with an intake port 23b for drawing refrigerant gas into the cylinder chamber 23a from outside the sealed container 10. The upper bearing 24 is provided with a discharge port (not shown) for discharging compressed refrigerant gas to the outside of the cylinder chamber 23a.

[0022] A discharge valve (not shown) is provided at the discharge port of the upper bearing 24. The discharge valve controls the timing of refrigerant gas discharge. Specifically, the discharge valve is closed until the pressure of the refrigerant gas in the cylinder chamber 23a rises to a predetermined pressure. When the pressure of the refrigerant gas in the cylinder chamber 23a rises above the predetermined pressure, the discharge valve opens, and the high-temperature, high-pressure refrigerant gas is discharged to the outside of the cylinder chamber 23a through the discharge port.

[0023] In the cylinder chamber 23a, the suction, compression, and discharge operations are repeated, so the refrigerant gas is discharged intermittently from the discharge port. This can generate noise such as pulsating sounds. To reduce noise, a discharge muffler 27 is attached to the outside of the upper bearing 24, that is, on the side of the upper bearing 24 facing the motor 30, so as to cover the upper bearing 24. The discharge muffler 27 is provided with discharge holes. The refrigerant gas compressed in the cylinder chamber 23a passes through the discharge port, is discharged into the space inside the discharge muffler 27, and then discharged into the sealed container 10 from the discharge holes.

[0024] An intake muffler 101 is provided on the side of the sealed container 10. The intake muffler 101 is provided on the intake side of the compressor 100 to prevent liquid refrigerant from being directly drawn into the cylinder chamber 23a. Generally, the compressor 100 receives a mixture of low-pressure refrigerant gas and liquid refrigerant from an external refrigerant circuit. If liquid refrigerant flows into the cylinder chamber 23a and is compressed by the compression mechanism 20, it will cause the compression mechanism 20 to malfunction. For this reason, the intake muffler 101 separates the liquid refrigerant and refrigerant gas, and only the refrigerant gas is sent to the cylinder chamber 23a. The intake muffler 101 is connected to the intake port of the cylinder 23 by an intake connecting pipe 101a. The low-pressure refrigerant gas sent from the intake muffler 101 is drawn into the cylinder chamber 23a via the intake connecting pipe 101a.

[0025] In the compression mechanism 20, the rotational motion of the rotating shaft 21 causes the eccentric shaft portion 21b to rotate within the cylinder chamber 23a. As a result, the rolling piston 22 rotates eccentrically along the inner circumferential surface of the cylinder 23. The volume of the working chamber, partitioned by the inner circumferential surface of the cylinder 23, the outer circumferential surface of the rolling piston 22, and the vanes, increases or decreases with the rotation of the eccentric shaft portion 21b. First, the working chamber and the intake port come into contact, and low-pressure refrigerant gas is drawn into the working chamber. Next, the intake port is closed, the volume of the working chamber decreases, and the refrigerant gas inside the working chamber is compressed. Next, the working chamber and the discharge port come into contact. When the pressure of the refrigerant gas inside the working chamber reaches a predetermined pressure, the discharge valve opens, and the compressed refrigerant gas is discharged to the outside of the cylinder chamber 23a.

[0026] The high-temperature, high-pressure refrigerant gas discharged from the cylinder chamber 23a into the sealed container 10 via the discharge muffler 27 passes through the electric motor 30 and rises within the sealed container 10. The high-temperature, high-pressure refrigerant gas is discharged to the outside of the sealed container 10 from the discharge pipe 102 located at the top of the sealed container 10. The refrigerant discharged from the compressor 100 circulates through the refrigerant circuit 201 and returns to the intake muffler 101.

[0027] In this embodiment, a rotary compressor is exemplified as the compressor 100, but various types of compressors, such as scroll compressors, can be used as the compressor 100.

[0028] Next, the flow of refrigerant in the refrigerant circuit 201 will be explained. For example, in the heating operation of the air conditioner, the four-way valve 103 is switched to form the flow path shown by the solid line in Figure 1. The high-temperature, high-pressure refrigerant gas compressed by the compressor 100 flows through the four-way valve 103 into the indoor heat exchanger 106. The refrigerant gas that flows into the indoor heat exchanger 106 condenses and liquefies through heat exchange with the indoor air, becoming liquid refrigerant. The liquid refrigerant that flows out of the indoor heat exchanger 106 is depressurized by the throttling device 105 and flows into the outdoor heat exchanger 104 in a low-temperature, low-pressure two-phase state. The two-phase refrigerant that flows into the outdoor heat exchanger 104 evaporates and gasifies through heat exchange with the outdoor air, becoming refrigerant gas. The refrigerant gas that flows out of the outdoor heat exchanger 104 returns to the intake muffler 101 of the compressor 100 through the four-way valve 103. In other words, the refrigerant circulates in the refrigerant circuit as shown by the solid arrow in Figure 1. In the outdoor heat exchanger 104, which acts as an evaporator, the refrigerant absorbs heat from the outdoor air. In the indoor heat exchanger 106, which acts as a condenser, the indoor air is warmed by the heat released from the refrigerant.

[0029] During the cooling operation of the air conditioner, the four-way valve 103 is switched to form the flow path shown by the dashed line in Figure 1. The high-temperature, high-pressure refrigerant gas compressed by the compressor 100 flows through the four-way valve 103 into the outdoor heat exchanger 104. The refrigerant gas flowing into the outdoor heat exchanger 104 condenses and liquefies through heat exchange with the outdoor air, becoming liquid refrigerant. The liquid refrigerant flowing out of the outdoor heat exchanger 104 is depressurized by the throttling device 105, becoming a low-temperature, low-pressure two-phase state, and flows into the indoor heat exchanger 106. The two-phase refrigerant flowing into the indoor heat exchanger 106 evaporates and gasifies through heat exchange with the indoor air, becoming refrigerant gas. The refrigerant gas flowing out of the indoor heat exchanger 106 returns to the intake muffler 101 of the compressor 100 through the four-way valve 103. In other words, the refrigerant circulates through the refrigerant circuit as shown by the dashed arrow in Figure 1. When switching from heating to cooling operation, the indoor heat exchanger 106 changes from a condenser to an evaporator, and the outdoor heat exchanger 104 changes from an evaporator to a condenser. In the indoor heat exchanger 106, which is an evaporator, the indoor air is cooled as the refrigerant absorbs heat from the indoor air. In the outdoor heat exchanger 104, which is a condenser, the refrigerant releases heat to the outdoor air.

[0030] Next, the refrigerant, odorant, and refrigerant oil used in the refrigeration cycle device 200 of this embodiment will be described.

[0031] The refrigerant is sealed in the refrigerant circuit 201. The refrigerant is, for example, a flammable refrigerant containing hydrocarbons with 1 to 4 carbon atoms. Examples of hydrocarbons with 1 to 4 carbon atoms include R-290 (propane), R-1270 (propylene), R-600 (butane), and R-600a (isobutane). The refrigerant is preferably propane, propylene, or a mixture thereof. This is because these have operating pressures suitable for use in the refrigeration cycle device 200. From the viewpoint of oxidation stability, the refrigerant is more preferably propane. According to the IPCC Sixth Assessment Report, the GWP value of propane is 0.02. Because propane has a very low GWP value and high cooling performance, it can contribute to reducing the environmental burden during the manufacture and operation of the refrigeration cycle device 200. The refrigerant may also be a mixture of hydrocarbons with 1 to 4 carbon atoms and halogenated hydrocarbons.

[0032] The odorant is sealed in the refrigerant circuit 201 together with the refrigerant. When the refrigerant leaks from the refrigerant circuit 201, the odorant leaks out of the refrigerant circuit 201 along with the refrigerant. Examples of odorants include sulfur-based odorants and amine-based odorants. Examples of sulfur-based odorants include mercaptans, sulfides, and thiophenes. Examples of mercaptans include methyl mercaptan (MM), ethyl mercaptan (EM), n-propyl mercaptan (NPM), isopropyl mercaptan (IPM), and tert-butyl mercaptan (TBM). Examples of sulfides include dimethyl sulfide (DMS), diethyl sulfide (DES), and methyl ethyl sulfide (MES). Examples of thiophenes include tetrahydrothiophene (THT). Other sulfur-based odorants include carbonyl sulfide and hydrogen sulfide. Examples of amine-based odorants include trimethylamine. These odorants are compounds with a proven track record of use in fuel gases and are compounds that produce unpleasant odors. These odorants may be used individually or in combination of two or more.

[0033] The odorant is preferably a sulfur-based odorant used in household fuel gases (e.g., MM, EM, NPM, IPM, TBM, DMS, DES, MES, THT, or a mixture thereof). By mixing a sulfur-based odorant used in household fuel gases with the refrigerant, the unpleasant odor characteristic of the sulfur-based odorant makes it easy for people to detect refrigerant leaks through their sense of smell. THT is more preferable as the sulfur-based odorant. THT is chemically more stable than mercaptans and sulfides, and is therefore less likely to undergo decomposition or corrosion reactions in the refrigerant circuit 201. In addition, since the melting point of THT is low at -96°C, THT is less likely to solidify in the refrigerant circuit 201.

[0034] The odorant is filled into the refrigerant circuit 201 so that the value of the filled odorant composition is between 1 ppm by mass and 10,000 ppm by mass. The filled odorant composition is expressed as mass of odorant / (mass of refrigerant + mass of odorant). If the filled odorant composition is less than 1 ppm by mass, the desired odor cannot be obtained. On the other hand, if the filled odorant composition is more than 10,000 ppm, the properties of the refrigerant oil will be inhibited due to dissolution in the refrigerant oil. The value of the filled odorant composition is preferably between 5 ppm by mass and 5,000 ppm by mass, and more preferably between 10 ppm by mass and 3,000 ppm by mass.

[0035] The refrigeration oil is filled into the compressor 100. A portion of the refrigeration oil may circulate in the refrigerant circuit 201 together with the refrigerant and odorant. The refrigeration oil contains a base oil. The base oil is at least one selected from the group consisting of oxygenated oils and hydrocarbon oils. Examples of oxygenated oils include polyalkylene glycol (PAG), polyol ester (POE), and polyvinyl ether (PVE). Examples of hydrocarbon oils include polyalphaolefin (PAO), alkylbenzene (AB), alkylnaphthalene (AN), and mineral oil.

[0036] Here, the base oil is a component that lubricates the inside of the compressor 100 due to the kinematic viscosity of the substance. The base oil is preferably a substance with a higher kinematic viscosity than the refrigerant, and has a kinematic viscosity of 5 mm at 40°C. ２ / s or more 250mm ２ A viscosity of less than or equal to / s is more preferable. By adjusting the molecular structure and degree of polymerization of each type of base oil, the kinematic viscosity of the base oil can be adjusted to the above range. Having a kinematic viscosity higher than that of the refrigerant allows the sliding parts of the compressor 100 to be sufficiently lubricated, and prevents a significant decrease in the cooling efficiency of the refrigeration cycle device 200.

[0037] Conventionally, in a refrigeration cycle device, a method for suppressing the dissolution of an odorant in refrigeration oil is known. In contrast, in the present embodiment, in order to actively discharge the refrigeration oil in which the odorant is dissolved from the compressor 100 and diffuse the odorant into the refrigerant circuit 201, it is desirable that a certain amount of the odorant dissolves in the refrigeration oil.

[0038] Oxygen-containing oils such as PAG, POE, and PVE contain a large amount of oxygen (O), which is an element with a high electronegativity, in their molecular structures. Therefore, they have a high polarity and can dissolve a large amount of odorants. This is because the odorant contains at least one of sulfur (S) and nitrogen (N), so the odorant also has polarity similar to the above-mentioned oxygen-containing oils. Furthermore, when a hydrocarbon having 1 to 4 carbon atoms is used as the refrigerant and the above-mentioned oxygen-containing oil is used as the refrigeration oil, the compatibility between the refrigerant and the refrigeration oil is low. Therefore, only the odorant can be selectively dissolved in the refrigeration oil. Therefore, when a hydrocarbon having 1 to 4 carbon atoms is used as the refrigerant, it is preferable to use an oxygen-containing oil such as PAG, POE, or PVE as the refrigeration oil.

[0039] FIG. 3 is a graph showing the temperature dependence of the odorant concentration in the discharged refrigerant in the present embodiment. The horizontal axis represents the reciprocal of the temperature (K －１ ). The vertical axis represents the common logarithm of the odorant concentration (mass ppm) in the discharged refrigerant. The odorant concentration in the discharged refrigerant is a value represented by the mass of the odorant / (the mass of the refrigerant + the mass of the odorant).

[0040] The graph in FIG. 3 was obtained by the following elemental experiment. First, a refrigerant, refrigeration oil, and an odorant were sealed in a closed container. Propane was used as the refrigerant and THT was used as the odorant. Next, the refrigerant was discharged from the closed container while allowing the refrigeration oil to remain in the closed container. The concentration of the odorant discharged together with the refrigerant was measured as the odorant concentration in the discharged refrigerant. This measurement was repeated while changing the temperature in the closed container. As shown in FIG. 3, the higher the temperature, the higher the odorant concentration in the discharged refrigerant.

[0041] Figure 4 is a graph showing the dependence of the concentration of the odorant in the discharged refrigerant on the refrigerant mass fraction in the present embodiment. The horizontal axis represents the refrigerant mass fraction (%) in the sealed container. The refrigerant mass fraction is a value represented by (mass of refrigerant + mass of odorant) / (mass of refrigerant + mass of odorant + mass of refrigerant oil). The vertical axis represents the concentration of the odorant in the discharged refrigerant (ppm by mass).

[0042] The graph in Figure 4 was obtained by conducting the above-described elemental experiment while changing the refrigerant mass fraction in the sealed container. As shown in Figure 4, the higher the refrigerant mass fraction, the higher the concentration of the odorant in the discharged refrigerant.

[0043] Figure 5 is a graph showing the dependence of the concentration of the odorant in the discharged refrigerant on the odorant composition in the present embodiment. The horizontal axis represents the filled odorant composition (ppm by mass) in the sealed container. The filled odorant composition in the sealed container is a value represented by mass of odorant / (mass of refrigerant + mass of odorant). The vertical axis represents the concentration of the odorant in the discharged refrigerant (ppm by mass).

[0044] The graph in Figure 5 was obtained by conducting the above-described elemental experiment while changing the filled odorant composition in the sealed container. As shown in Figure 5, the higher the filled odorant composition, the higher the concentration of the odorant in the discharged refrigerant.

[0045] By using the graphs in Figures 3 to 5 and setting the filled odorant composition to a value within the range of 10 ppm by mass or more and 3000 ppm by mass or less, the graphs shown in Figures 6 and 7 are obtained. Figures 6 and 7 are graphs showing the relationship between the oil circulation rate and the equivalent value of the odor index in the refrigeration cycle device according to the present embodiment. Each horizontal axis in Figures 6 and 7 represents the oil circulation rate (wt%). In Figure 6, the range of the oil circulation rate from 0 wt% to 10 wt% is shown. In Figure 7, the range of the oil circulation rate from 0 wt% to 0.5 wt% is shown in an enlarged manner. Each vertical axis in Figures 6 and 7 represents the equivalent value of the odor index when the refrigerant leaks from the refrigerant circuit.

[0046] The oil circulation rate is calculated using the oil circulation rate measurement method specified in JIS B 8606. The test conditions are ARI conditions (condensation temperature / evaporation temperature = 54.4 / 7.2°C, degree of supercooling / degree of superheating = 8.3 / 11.1°C, dew point method). The compressor rotation speed is the maximum rotation speed of the compressor 100 used in the refrigeration cycle device 200. The oil circulation rate is the ratio of the mass of refrigerant oil to the total mass of the mixed fluid, such as refrigerant, odorant, and refrigerant oil, circulating in the refrigerant circuit.

[0047] The odor index has the following relationship with the odor intensity in the six-level odor intensity scale, as shown in Table 1 below.

[0048]

[0049] Odor intensity 1 (detection threshold) represents an odor intensity that is "barely perceptible." Odor intensity 1 is the minimum odor intensity at which an odor can be detected, even if the type of odor is unknown. Odor intensity 1 corresponds to an odor index of 5 or higher. Odor intensity 2 (recognition threshold) represents an odor intensity that is "weak enough to recognize what the odor is." Odor intensity 2 is the minimum odor intensity at which the type of odor can be detected. Odor intensity 2 corresponds to an odor index of 10 or higher. Odor intensity 3 represents an odor intensity that is "easily perceptible." Odor intensity 3 corresponds to an odor index of 15 or higher. Odor intensity 4 represents an odor intensity that is "strong." Odor intensity 4 corresponds to an odor index of 20 or higher. Odor intensity 5 represents an odor intensity that is "intense." Odor intensity 5 corresponds to an odor index of 25 or higher.

[0050] If refrigerant leaks from the refrigerant circuit 201, the odorant inside the refrigerant circuit 201 will leak to the outside along with the refrigerant. For a refrigerant leak to be detected by a person's sense of smell, it is desirable that the odor intensity be 1 (detection threshold) or higher. To more reliably detect a refrigerant leak, it is desirable that the odor intensity be 2 (recognition threshold) or higher so that a person can recognize it as an unpleasant odor. For easy detection of a refrigerant leak, it is desirable that the odor intensity be 3 or higher. On the other hand, to prevent the generation of a strong odor, it is desirable that the odor intensity be 4 or lower.

[0051] As shown in Figures 6 and 7, the odor index equivalent value increases as the oil circulation rate increases. This is because the odorant dissolved in the refrigerant oil diffuses into the refrigerant circuit 201 together with the refrigerant oil. When the oil circulation rate is 0.01 wt%, the odor index equivalent value is 5, meaning the odor intensity is 1 (detection threshold). Therefore, in order for refrigerant leakage to be recognized by the human sense of smell, it is desirable for the oil circulation rate to be 0.01 wt% or higher. To provide a margin above the detection threshold and make refrigerant leakage easier to recognize, it is even more desirable for the oil circulation rate to be 0.03 wt% or higher.

[0052] When the oil circulation rate is 0.05 wt%, the odor index equivalent value is 10, meaning the odor intensity is 2 (perceptible threshold). Therefore, in order to more reliably detect refrigerant leakage by human sense of smell, it is desirable for the oil circulation rate to be 0.05 wt% or higher.

[0053] When the oil circulation rate is 0.3 wt%, the odor index equivalent value is 15, meaning the odor intensity is 3. Therefore, to easily detect refrigerant leaks, it is desirable for the oil circulation rate to be 0.3 wt% or higher.

[0054] On the other hand, when the oil circulation rate exceeds 7 wt%, the odor index equivalent value becomes 25 or higher, meaning the odor intensity becomes 5. Therefore, to prevent the generation of strong odors in the event of a refrigerant leak, it is desirable that the oil circulation rate be 7 wt% or less.

[0055] In the refrigeration cycle device 200 of this embodiment, the compressor 100 is operated in a manner that provides the above-described range of oil circulation rates for at least a portion of the operating period of the refrigeration cycle device 200. As a result, the odorant dissolved in the refrigerant oil is sufficiently diffused throughout the refrigerant circuit 201. In other words, the compressor 100 does not need to operate in a manner that provides the above-described range of oil circulation rates at all times; it is sufficient if it is capable of performing such an operation.

[0056] If the refrigeration cycle unit 200 is operated at a low load for a long period of time, the above-mentioned range of oil circulation rates may not be obtained over that period. In this case, the compressor 100 may be operated periodically to obtain the above-mentioned range of oil circulation rates, regardless of the load required by the refrigeration cycle unit 200.

[0057] As described above, the refrigeration cycle device 200 according to this embodiment includes a refrigerant circuit 201 including a compressor 100. The refrigerant circuit 201 is filled with refrigerant and odorant. The compressor 100 is filled with refrigerant oil. The oil circulation rate of the refrigerant circuit 201 is 0.01 wt% or more.

[0058] With this configuration, an odor above the detection threshold is generated when a refrigerant leak occurs, allowing for more reliable detection of the refrigerant leak by human sense of smell. In other words, in this embodiment, instead of suppressing the dissolution of the odorant into the refrigerant oil, the odorant is dissolved in the refrigerant oil and then the refrigerant oil is actively discharged from the compressor 100, thereby diffusing the odorant into the refrigerant circuit 201.

[0059] In the refrigeration cycle device 200 according to this embodiment, the oil circulation rate is 7 wt% or less. This configuration prevents the generation of a strong odor in the event of refrigerant leakage.

[0060] In the refrigeration cycle device 200 according to this embodiment, the oil circulation rate is 0.05 wt% or more. With this configuration, when refrigerant leaks, an odor above the recognition threshold is generated, allowing people to recognize it as an unpleasant odor. Therefore, refrigerant leaks can be more reliably detected by the human sense of smell.

[0061] In the refrigeration cycle device 200 according to this embodiment, the oil circulation rate is 0.3 wt% or more. With this configuration, an odor that can be easily detected when refrigerant leakage occurs is generated, making it easy to detect refrigerant leakage.

[0062] In the refrigeration cycle device 200 according to this embodiment, the refrigerant contains a hydrocarbon with 1 to 4 carbon atoms. The refrigeration oil is polyalkylene glycol, polyol ester, or polyvinyl ether polyalkylene. With this configuration, the compatibility between the refrigerant and the refrigeration oil is reduced, so that only the odorant can be selectively dissolved in the refrigeration oil.

[0063] Embodiment 2. A refrigeration cycle device according to Embodiment 2 will be described. Figure 8 is a graph showing the relationship between the oil circulation rate and the performance effect in the refrigeration cycle device according to this embodiment. The horizontal axis represents the oil circulation rate (wt%). The vertical axis represents the performance effect (%) of the compressor 100. As shown in Figure 8, the performance of the compressor 100 decreases as the oil circulation rate increases. However, if the oil circulation rate is 5 wt% or less, there is almost no decrease in the performance of the compressor 100. Therefore, in order to suppress the decrease in the performance of the compressor 100, it is desirable that the oil circulation rate be 5 wt% or less.

[0064] As described above, in the refrigeration cycle device 200 according to this embodiment, the oil circulation rate is 5 wt% or less. This configuration makes it possible to suppress the deterioration of the compressor 100's performance.

[0065] Embodiment 3. A refrigeration cycle device according to Embodiment 3 will be described. Figure 9 is a graph showing the relationship between the oil circulation rate and the mass ratio of refrigerant to refrigerant oil in the refrigeration cycle device according to this embodiment. The horizontal axis represents the ratio of the mass of refrigerant sealed in the refrigerant circuit 201 to the mass of refrigerant oil filled in the compressor 100. The vertical axis represents the oil circulation rate (wt%). In the graph of Figure 9, several points are plotted where an odor with an odor index of 5 (detection threshold) is generated when refrigerant leaks. Line L1 is an approximate straight line of the plotted points. Line L2 is a straight line where the oil circulation rate is 0.01 wt%. If the oil circulation rate is greater than line L1 and also greater than line L2, an odor with an odor index of 5 or higher is generated when refrigerant leaks.

[0066] Let Ro be the oil circulation rate (wt%), Mref be the mass of the refrigerant (g), and Moil be the mass of the refrigerant oil (g). Then, line L1 is Ro = -9.37 × 10⁻⁶－３ ×Mref / Moil + 5.63×10 －２ It is represented by, and the line L2 is represented by Ro = 0.01 wt%. If both of the relationships of the following formulas (1) and (2) are satisfied, an odor with an odor index of 5 or more will occur when the refrigerant leaks. Ro ≥ -9.37×10 －３ ×Mref / Moil + 5.63×10 －２ ...(1) Ro ≥ 0.01 wt% ...(2)

[0067] As described above, in the refrigeration cycle device 200 according to the present embodiment, the oil circulation rate is Ro, the mass of the refrigerant enclosed in the refrigerant circuit 201 is Mref, and the mass of the refrigeration machine oil filled in the compressor 100 is Moil. At this time, Ro ≥ -9.37×10 －３ ×Mref / Moil + 5.63×10 －２ and the relationship of Ro ≥ 0.01 wt% is satisfied.

[0068] [[ID=I7]] According to this configuration, since an odor above the detection threshold occurs when the refrigerant leaks, the leakage of the refrigerant can be more reliably recognized by human olfaction.

[0069] 10 Sealed container, 11 Body portion, 12 Upper lid portion, 13 Lower lid portion, 14 Refrigeration machine oil, 20 Compression mechanism, 21 Rotating shaft, 21a Main shaft portion, 21b Eccentric shaft portion, 21c Sub-shaft portion, 22 Rolling piston, 23 Cylinder, 23a Cylinder chamber, 23b Suction port, 24 Upper bearing, 25 Lower bearing, 27 Discharge muffler, 30 Electric motor, 31 Rotor, 32 Stator, 100 Compressor, 101 Suction muffler, 101a Suction connection pipe, 102 Discharge pipe, 103 Four-way valve, 104 Outdoor heat exchanger, 105 Throttling device, 106 Indoor heat exchanger, 200 Refrigeration cycle device, 201 Refrigerant circuit.

Claims

1. A refrigeration cycle device comprising a refrigerant circuit including a compressor, wherein the refrigerant circuit is filled with a refrigerant and an odorant, the compressor is filled with refrigerant oil, and the oil circulation rate of the refrigerant circuit is 0.01 wt% or more.

2. The refrigeration cycle device according to claim 1, wherein the oil circulation rate is 7 wt% or less.

3. The refrigeration cycle device according to claim 1 or claim 2, wherein the oil circulation rate is 0.05 wt% or more.

4. The refrigeration cycle device according to any one of claims 1 to 3, wherein the oil circulation rate is 0.3 wt% or more.

5. The refrigeration cycle device according to any one of claims 1 to 4, wherein the oil circulation rate is 5 wt% or less.

6. When the oil circulation rate is R, the mass of the refrigerant sealed in the refrigerant circuit is Mref, and the mass of the refrigerant oil filled in the compressor is Moil, then R ≥ -9.37 × 10 －３ ×Mref / Moil+5.63×10 －２ A refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the relationship Ro ≥ 0.01 wt% is satisfied.

7. The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the refrigerant contains a hydrocarbon having 1 to 4 carbon atoms, and the refrigeration oil is polyalkylene glycol, polyol ester, or polyvinyl ether polyalkylene.

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