WO2015114783A1 - Compressor and refrigeration cycle device - Google Patents

Abstract

The present invention is equipped with: a compression mechanism unit (35) that compresses a refrigerant and is provided within a shell (8) serving as a sealed container; a crankshaft (4) that imparts rotational force to the compression mechanism unit (35); a bearing (3a) that holds the crankshaft (4); and an oil pump (21) that supplies refrigerant oil to the bearing (3a). The displacement volume (Vst) [cc/rev] of the refrigerant in the compression mechanism unit (35) satisfies the relationship 20 ≤ Vst ≤ 35 [cc/rev], and an ester oil for which the kinetic viscosity (ν) [mm²/s] at 40°C satisfies the relationship 480/(6.5 - 0.13×Vst) < ν < 300 [mm²/s] and having a viscosity index of 80-200 is used as the refrigerant oil.

Description

Compressor and refrigeration cycle apparatus

This invention relates to a compressor and the like. In particular, the present invention relates to a compressor or the like used in a refrigeration cycle apparatus in which a plurality of refrigerant circuits are configured in multiple stages.

In a refrigeration cycle apparatus having a plurality of refrigerant circuits configured in multiple stages, when the low-side refrigerant is carbon dioxide, the high-side compressor is started first, and the low-side compressor is started after a predetermined time has elapsed. Thus, a technique is known that can avoid the problem of a sudden increase in discharge pressure and lower the design pressure (see, for example, Patent Document 1).

In addition, a technique is known in which carbon dioxide is used as a refrigerant, and ester oil having a kinematic viscosity at 40 ° C. of 50 to 200 mm ² / s and a viscosity index of 80 to 200 is used as a refrigerating machine oil (see, for example, Patent Document 2). By using the ester oil as the refrigerating machine oil, the high-pressure viscosity of the ester oil can enhance the lubricity and lower the viscosity as compared with the case of using the polyalkylene glycol oil, and the power loss due to the viscosity can be reduced.

Published Japanese Patent Application Laid-Open No. 2004-190917 (page 14, FIG. 1) JP 2008-121625 A (6th page, Fig. 1)

For example, in a binary refrigeration cycle apparatus or the like, when the low-side refrigerant is carbon dioxide and the displacement amount is large in the compressor, the load acting on the bearing becomes large. For this reason, the design pressure is lowered by using ester oil with a kinematic viscosity of 50 to 200 mm ² / s and starting the low-end compressor after starting the high-end compressor first. Even so, the carbon dioxide refrigerant is easily dissolved in the ester oil, and the kinematic viscosity is significantly reduced. Therefore, there has been a problem that the oil film thickness of the bearing cannot be ensured and the bearing is worn. On the other hand, when the kinematic viscosity is too high, there is a problem that the sliding loss of the bearing increases and the performance deteriorates.

The present invention has been made to solve the above-described problems, and provides a compressor and the like that can achieve both reliability and performance.

A compressor according to the present invention is provided in a sealed container, and includes a compression mechanism portion that compresses a refrigerant having carbon dioxide, a shaft that applies rotational force to the compressor mechanism portion, a bearing that holds the shaft, and a bearing. An oil pump that supplies refrigeration oil, and the displacement Vst [cc / rev] of the refrigerant in the compression mechanism section satisfies 20 ≦ Vst ≦ 35 [cc / rev], and the kinematic viscosity ν [mm] at 40 [° C.] ² / s] satisfies 480 / (6.5-0.13 × Vst) <ν <300 [mm ² / s], and ester oil having a viscosity index of 80 to 200 is used as the refrigerating machine oil.

In the compressor of the present invention, the displacement amount Vst [cc / rev] satisfies 20 ≦ Vst ≦ 35 [cc / rev], and the kinematic viscosity ν [mm ² / s] is 480 / (6.5-0 .13 × Vst) <ν <300 [mm ² / s] and an ester oil having a viscosity index of 80 to 200 is used as a refrigerating machine oil, thus enabling appropriate kinematic viscosity and driving, reliability and performance Can be secured.

It is a figure showing the structure of the binary refrigeration apparatus in Embodiment 1 of this invention. It is a figure which shows the structure of the compressor 50 which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the temperature in the refrigerant | coolant atmosphere in Embodiment 1 of this invention, and the kinematic viscosity of general refrigerating machine oil. It is a figure which shows the relationship between the amount of displacement and bearing load in Embodiment 1 of this invention. It is a figure which shows the relationship between the amount of displacement in Embodiment 1 of this invention, and kinematic viscosity of refrigeration oil. It is a figure which shows the relationship between the rotation speed of the compressor 50 in Embodiment 1 of this invention, and the oil film thickness of a bearing.

Hereinafter, a refrigeration cycle apparatus and the like according to embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals denote the same or corresponding parts, and are common to all the embodiments described below. And the form of the component represented by the whole specification is an illustration to the last, Comprising: It does not limit to the form described in the specification. In particular, the combination of the components is not limited to the combination in each embodiment, and the components described in the other embodiments can be applied to another embodiment. Here, the levels of temperature, pressure, and the like are not particularly determined in relation to absolute values, but are relatively determined in terms of the state and operation of the system, apparatus, and the like. In addition, when there is no need to particularly distinguish or identify a plurality of similar devices that are distinguished by subscripts, the subscripts may be omitted. In the drawings, the relationship between the sizes of the constituent members may be different from the actual one.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a binary refrigeration apparatus in Embodiment 1 of the present invention. As shown in FIG. 1, the binary refrigeration apparatus in the present embodiment includes a low-source refrigeration cycle 100 and a high-source refrigeration cycle 200, and configures a refrigerant circuit that circulates refrigerant independently of each other. In order to configure the two refrigerant circuits in multiple stages, a cascade condenser (refrigerant) in which the high-side evaporator 240 and the low-side condenser 120 are combined so as to enable heat exchange between the refrigerants passing through them respectively. An intermediate heat exchanger) 300 is provided.

In FIG. 1, a low-source refrigeration cycle 100 includes a low-side compressor 110, a low-side condenser 120, a low-side expansion valve 130, and a low-side evaporator 140 connected in this order through a refrigerant pipe. Hereinafter, the low-source side refrigerant circuit is configured. On the other hand, the high-source refrigeration cycle 200 is configured by connecting a high-side compressor 210, a high-side condenser 220, a high-side expansion valve 230, and a high-side evaporator 240 in order through a refrigerant pipe (hereinafter referred to as a refrigerant circuit). High-end refrigerant circuit).

The low-source side compressor 110 of the low-source refrigeration cycle 100 sucks the refrigerant, compresses it, and discharges it in a high temperature / high pressure state. Here, for example, it is configured by a compressor of a type that can control the number of revolutions by an inverter circuit or the like and adjust the discharge amount of the high-side refrigerant. The configuration of the compressor will be described later.

Further, the low-side condenser 120 exchanges heat with the refrigerant discharged from the low-side compressor 110, condenses the refrigerant into a liquid refrigerant (condenses and liquefies). For example, in this case, in the cascade condenser 300, a heat transfer tube or the like through which the refrigerant flowing through the low-side refrigerant circuit passes becomes the low-side condenser 120, and heat exchange with the refrigerant flowing through the high-side refrigerant circuit is performed. To do.

The low-side expansion valve 130 serving as a decompression device, a throttling device or the like decompresses the refrigerant flowing through the low-side refrigerant circuit and expands it. For example, the flow rate control means such as an electronic expansion valve, a capillary (capillary), a refrigerant flow rate control means such as a temperature-sensitive expansion valve, and the like are used. The low element side evaporator 140 evaporates the refrigerant flowing through the low element refrigerant circuit by heat exchange with the object to be cooled, for example, to make a gas (gas) refrigerant (evaporate gas). The object to be cooled is cooled directly or indirectly by heat exchange with the refrigerant.

On the other hand, the high-side compressor 210 of the high-side refrigeration cycle 200 sucks the refrigerant flowing through the high-side refrigerant circuit, compresses the refrigerant, and discharges it in a high temperature / high pressure state. The high-end compressor 210 is also composed of, for example, a compressor having an inverter circuit or the like and capable of adjusting the refrigerant discharge amount. The configuration of the compressor will be described later.

The high-side condenser 220 performs heat exchange between, for example, air, brine, and the refrigerant flowing through the high-side refrigerant circuit to condense and liquefy the refrigerant. Here, in the present embodiment, heat exchange between the outside air and the refrigerant is performed, and a high-side condenser fan (not shown) for promoting heat exchange is provided. The high-end condenser fan is a fan that can adjust the air volume.

The high-side expansion valve 230 serving as a decompression device, a throttling device or the like decompresses the refrigerant flowing through the high-side refrigerant circuit and expands it. For example, the flow rate control means such as the electronic expansion valve described above and the refrigerant flow rate control means such as a capillary tube are used. The high element side evaporator 240 evaporates the refrigerant flowing through the high element side refrigerant circuit by heat exchange. For example, here, in the cascade condenser 300, a heat transfer tube or the like through which the refrigerant flowing through the high-side refrigerant circuit passes becomes the high-side evaporator 240, and heat exchange with the refrigerant flowing through the low-side refrigerant circuit is performed. To do.

Further, the cascade condenser 300 has the functions of the high-end evaporator 240 and the low-end condenser 120 described above, and enables the heat exchange between refrigerants to exchange heat between the high-end refrigerant and the low-end refrigerant. It is. By configuring the high-side refrigerant circuit and the low-side refrigerant circuit in a multistage configuration via the cascade capacitor 300 and performing heat exchange between the refrigerants, independent refrigerant circuits can be linked. By configuring the cascade condenser 300 with the high-side evaporator 240 and the low-side condenser 120, the respective refrigerant pressures are prevented from increasing in the two refrigerant circuits.

And in this Embodiment, the outdoor unit has the low original side compressor 110 and the low original side condenser 120 (cascade condenser 300) of the high original refrigerating cycle 200 and the low original refrigerating cycle 100. Further, the low-source side expansion valve 130 and the low-source side evaporator 140 of the low-source refrigeration cycle 100 have a freezer such as a supermarket showcase.

Here, CO ₂ (carbon dioxide), which has a small influence on global warming, is used as a low-side refrigerant that circulates through the low-side refrigerant circuit of the low-source refrigeration cycle 100 in consideration of refrigerant leakage. On the other hand, the high-source side refrigerant used in the high-source refrigeration cycle 200 uses R32 or the like.

FIG. 2 is a diagram showing the configuration of the compressor 50 according to Embodiment 1 of the present invention. FIG. 2 shows an example of a hermetic scroll compressor (low pressure shell type) in which a low pressure side (suction side) refrigerant acts on a hermetic container. The compressor 50 is a compressor that can be applied to the high-side compressor 210 and the low-side compressor 110 described above.

The compressor 50 in FIG. 2 has a function of sucking a refrigerant (which may be another fluid, but here a refrigerant), compressing it, and discharging it in a high temperature / high pressure state. The compressor 50 is configured such that a compression mechanism 35, a drive mechanism 36, and other components are accommodated in a shell 8 that is a sealed container constituting an outer shell. As shown in FIG. 2, in the shell 8, the compression mechanism part 35 is arrange | positioned at the upper side, and the drive mechanism part 36 is arrange | positioned at the lower side. Below the shell 8 is an oil sump 12.

The compression mechanism 35 has a function of compressing the refrigerant sucked from the suction pipe 5 and discharging it to the high-pressure space 15 formed above the shell 8. The high-pressure refrigerant in the high-pressure space 15 is discharged from the discharge pipe 13 to the outside of the compressor 50. Further, the drive mechanism unit 36 functions to drive the orbiting scroll 2 constituting the compression mechanism unit 35 in order to compress the refrigerant by the compression mechanism unit 35. When the drive mechanism unit 36 drives the orbiting scroll 2 via the crankshaft 4, the compression mechanism unit 35 compresses the refrigerant.

The compression mechanism unit 35 includes a fixed scroll 1 and a swing scroll 2. As shown in FIG. 2, the orbiting scroll 2 is disposed on the lower side, and the fixed scroll 1 is disposed on the upper side. The fixed scroll 1 is composed of a first spiral body 1b which is a first spiral projection provided upright on one surface of the first base plate 1c and the first base plate 1c. The orbiting scroll 2 includes a second spiral body 2b which is a spiral projection provided upright on one surface of the second base plate 2c and the second base plate 2c. The fixed scroll 1 and the orbiting scroll 2 are mounted in the shell 8 with the first spiral body 1b and the second spiral body 2b meshing with each other. And between the 1st spiral body 1b and the 2nd spiral body 2b, the compression chamber 9 which reduces when a volume goes to a radial inside is formed.

The fixed scroll 1 is fixed in the shell 8 through the frame 3. A discharge port 1 a that discharges a compressed and high-pressure refrigerant is formed at the center of the fixed scroll 1. A leaf spring valve 11 is disposed at the outlet opening of the discharge port 1a so as to cover the outlet opening and prevent reverse flow of the refrigerant. A valve presser 10 that restricts the lift amount of the valve 11 is provided on one end side of the valve 11. For this reason, when the refrigerant is compressed to a predetermined pressure in the compression chamber 9, the valve 11 is lifted against the elastic force, and the compressed refrigerant is discharged from the discharge port 1 a into the high-pressure space 15, and the discharge pipe 13. And is discharged to the outside of the compressor 50.

The orbiting scroll 2 performs an eccentric turning motion without rotating with respect to the fixed scroll 1. A hollow cylindrical concave bearing 2d that receives a driving force is formed at a substantially central portion of a surface (hereinafter referred to as a thrust surface) opposite to the surface on which the second spiral body 2b is formed of the orbiting scroll 2. Yes. An eccentric pin portion 4a provided at the upper end of a crankshaft 4 to be described later is fitted (engaged) with the concave bearing 2d.

The drive mechanism portion 36 is fixedly held inside the shell 8, is rotatably disposed on the inner peripheral surface side of the stator 7, and is vertically accommodated in the rotor 6 and the shell 8 fixed to the crankshaft 4. And at least a crankshaft 4 that is a rotating shaft. The stator 7 has a function of rotating the rotor 6 when energized. In addition, the outer peripheral surface of the stator 7 is fixedly supported on the shell 8 by shrink fitting or the like. The rotor 6 has a function of rotating and driving the crankshaft 4 when the stator 7 is energized. The rotor 6 is fixed to the outer periphery of the crankshaft 4, has a permanent magnet inside, and is held with a slight gap from the stator 7.

The crankshaft 4 rotates with the rotation of the rotor 6 and drives the orbiting scroll 2 to rotate. The crankshaft 4 is rotatably supported by a bearing portion 3a whose upper side is positioned at the center of the frame 3. Further, the lower side is rotatably supported by a sub bearing 16 a located at the center of a sub frame 16 fixedly arranged below the shell 8. At the upper end of the crankshaft 4 is formed an eccentric pin portion 4a that fits with the concave bearing 2d so that the orbiting scroll 2 can rotate while being eccentric.

The shell 8 is connected to a suction pipe 5 for sucking the refrigerant and a discharge pipe 13 for discharging the refrigerant.

The frame 3 is fixed inside the shell 8. The frame 3 is fixed to the inner peripheral surface of the shell 8, and a through hole is formed at the center for supporting the crankshaft 4. The frame 3 supports the swing scroll 2 and also supports the crankshaft 4 in a freely rotatable manner by a bearing portion 3a. Note that the outer peripheral surface of the frame 3 may be fixed to the inner peripheral surface of the shell 8 by shrink fitting, welding, or the like. A subframe 16 is fixed inside the shell 8. The subframe 16 is fixed to the inner peripheral surface of the shell 8, and a through hole is formed in the center for supporting the crankshaft 4. The subframe 16 rotatably supports the crankshaft 4 with a subbearing 16a. Here, the frame 3 is fixed to the upper side, and the subframe 16 is fixed to the lower side.

Here, an Oldham ring 20 is disposed in the shell 8 to prevent the rotation of the orbiting scroll 2 during the eccentric orbiting motion. The Oldham ring 20 is disposed between the fixed scroll 1 and the orbiting scroll 2 and functions to prevent the revolving motion of the orbiting scroll 2 and to enable a revolving motion.

The oil pump 21 is fixed to the lower side of the crankshaft 4. The oil pump 21 is a positive displacement pump and functions to supply refrigerating machine oil stored in the oil reservoir 12 to the concave bearing 2d and the bearing portion 3a through an oil circuit 22 provided in the crankshaft 4 as the crankshaft 4 rotates. Fulfill.

Here, the operation of the compressor 50 of the present embodiment will be briefly described. When a power supply terminal (not shown) provided in the shell 8 is energized, torque is generated in the stator 7 and the rotor 6 and the crankshaft 4 rotates. The rocking scroll 2 is fitted to the eccentric pin portion 4a of the crankshaft 4 so as to be rotatable. The orbiting scroll 2 having the spiral bodies (first spiral body 1b and second spiral body 2b) created following the involute curve meshes with the fixed scroll 1, thereby forming a plurality of compression chambers 9. The compression chamber 9 moves while reducing the volume toward the center along with the turning motion of the orbiting scroll 2, and the refrigerant is compressed.

The oil pump 21 sucks refrigeration oil from the oil sump 12 as the crankshaft 4 rotates. The sucked refrigerating machine oil is supplied to the concave bearing 2d and the bearing portion 3a through the oil circuit 22 inside the crankshaft 4 to generate an oil film on the bearing, thereby preventing wear and ensuring reliability.

FIG. 3 is a diagram showing the relationship between the temperature in the refrigerant atmosphere and the kinematic viscosity of a general refrigerating machine oil according to Embodiment 1 of the present invention. The kinematic viscosity of the refrigerating machine oil is determined from the pressure and temperature of the refrigerant atmosphere when supplied to the bearing. FIG. 3 shows that the higher the temperature and the higher the pressure, the more the refrigerant dissolves in the refrigerating machine oil and the kinematic viscosity decreases. In particular, since carbon dioxide has a high pressure and the refrigerant dissolves well in refrigerating machine oil, the amount of decrease in kinematic viscosity is large.

In recent years, switching to a refrigerant with a low global warming potential (GWP) has been studied from the viewpoint of preventing global warming. Since carbon dioxide has GWP = 1, the environmental impact is small, but the operating pressure is four times that of the HFC refrigerant. For this reason, the load to the compressor 50 becomes large and performance becomes low. Therefore, by configuring a binary refrigeration cycle apparatus and using low-carbon refrigerant as carbon dioxide, the overall environmental load and operating pressure are improved.

As described above, when carbon dioxide is used, the amount of decrease in kinematic viscosity of the refrigerating machine oil increases. In order to suppress a decrease in viscosity in a carbon dioxide atmosphere, there is a method using polyalkylene glycol as a refrigerating machine oil. Since carbon dioxide has the property of being hardly soluble in polyalkylene glycol, the viscosity of the refrigerating machine oil can be secured. Here, in the refrigeration apparatus and the air conditioner, the piping length of the refrigerant circuit becomes long. For this reason, when the refrigerating machine oil is polyalkylene glycol, the refrigerating machine oil discharged from the compressor is stagnated in the pipe and is not returned to the compressor, and the refrigerating machine oil may be depleted in the compressor. When the refrigeration oil is depleted, the compressor bearing is damaged.

On the other hand, when the refrigerating machine oil is ester oil, carbon dioxide dissolves well in ester oil. For this reason, there is little quantity that refrigeration oil stagnates in piping, and it is hard to generate the malfunction that refrigeration oil runs out. Therefore, in the present embodiment, ester oil is used as refrigerating machine oil in a refrigeration apparatus, an air conditioner or the like having a long pipe length. Here, although the viscosity of refrigerating machine oil falls because a carbon dioxide melt | dissolves in ester oil, it solves by making the viscosity of ester oil high.

FIG. 4 is a diagram showing the relationship between the displacement and the bearing load in Embodiment 1 of the present invention. FIG. 4 shows the relationship between the displacement of the concave bearing 2d and the bearing portion 3a and the bearing load. As the displacement increases, the power for compressing the refrigerant also increases. For this reason, the load of the bearing which receives the reaction force which compresses a refrigerant | coolant also increases. Therefore, when the displacement is increased, the viscosity of the ester oil needs to be increased. However, when the viscosity of the ester oil is excessively increased, the sliding loss in the bearing or the like increases. For this reason, it is desirable to set it as an appropriate viscosity.

FIG. 5 is a diagram showing the relationship between the displacement and the kinematic viscosity of the refrigerating machine oil according to Embodiment 1 of the present invention. Considering from FIG. 5, in order for the oil film thickness of the bearing to exceed that of the HFC refrigerant model, reliability should be satisfied if kinematic viscosity ν> 480 / (6.5-0.13 × Vst) [mm ² / s] is satisfied. We think that we can secure. Moreover, when kinematic viscosity becomes high too much, a sliding loss will increase and performance will fall. For this reason, it is necessary to satisfy the kinematic viscosity ν <300 [mm ² / s] at the same time. Here, the kinematic viscosity is preferably close to the lower limit satisfying ν> 480 / (6.5-0.13 × Vst) because the sliding loss can be minimized.

FIG. 6 is a diagram showing the relationship between the rotational speed of the compressor 50 and the oil film thickness of the bearing in Embodiment 1 of the present invention. The oil film thickness in the compressor 50 of the present embodiment represents a result when Vst = 30 [cc / rev] and ν = 190 [mm ² / s]. As shown in FIG. 6, in the compressor 50 of the present embodiment, the oil film thickness is ensured more than the HFC refrigerant model. For this reason, the reliability of the bearing is sufficiently secured.

Here, in the dual refrigeration cycle apparatus of the present embodiment, as shown in FIG. 2, a low-pressure shell type compressor 50 is used. The airtight container specifications of the compressor are roughly classified into a high pressure shell type in which only the high pressure side (discharge side) refrigerant acts on the airtight container and a low pressure shell type in which only the low pressure side refrigerant acts.

In the case of a high-pressure shell type compressor, the refrigerant returned from the refrigerant circuit (low-pressure side refrigerant) flows directly into the compression chamber through the suction pipe of the compressor and is compressed into a high-temperature / high-pressure refrigerant. The compressed refrigerant fills the inside of the sealed container and then discharges out of the compressor through the discharge pipe. Therefore, the oil reservoir portion in which the refrigeration oil is accumulated is a high-pressure refrigerant atmosphere.

On the other hand, in the case of a low-pressure shell type compressor, the refrigerant returned from the refrigerant circuit fills the compressor sealed container via the compressor suction pipe, flows into the compression chamber, is compressed, and is compressed with high-temperature and high-pressure refrigerant. Become. The compressed refrigerant is discharged out of the compressor through the discharge port and the discharge pipe. Therefore, the oil reservoir portion becomes a low-pressure refrigerant atmosphere.

As shown in FIG. 3, as the temperature is higher and the pressure is higher, the refrigerant dissolves in the refrigeration oil, and the kinematic viscosity of the refrigeration oil decreases. Accordingly, the low-pressure shell type, which has a low temperature and a low pressure, can be prevented from lowering the kinematic viscosity of the refrigerating machine oil and the reliability of the bearing (compressor) can be improved than the high-pressure shell type in a high-temperature / high-pressure atmosphere. In addition, since carbon dioxide has a high operating pressure, in the high-pressure shell type compressor, the thickness of the shell 8 must be increased, which increases the cost. Therefore, the low pressure shell type is more advantageous in that the cost can be kept low.

Further, as described above, a refrigerant having a low GWP is demanded. For this reason, it is desirable that the high-source side refrigerant of the binary refrigeration cycle apparatus also has a low GWP. As a refrigerant having a low GWP, for example, there is R32 having characteristics similar to R410A in the case of an HFC refrigerant. Natural refrigerants include carbon dioxide, propane, and ammonia. There is a hydrofluoroolefin (HFO) refrigerant having a carbon-carbon double bond. As typical HFO refrigerants, 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,1,2-tri Fluoroethylene (HFO-1123) is known. Regarding natural refrigerant, when carbon dioxide is used in the high-side refrigerant circuit, the operating pressure becomes 10 [MPa] or more. In addition, it is difficult to secure safety for refrigeration and air conditioners with large capacities that have a large displacement of propane and ammonia, and it is difficult to adopt them. Further, in the cascade capacitor 300, the heat balance between the evaporation heat of the high-side refrigerant circuit and the condensation heat of the low-side refrigerant circuit must be balanced. For this reason, when the low source side refrigerant is carbon dioxide, the selection of the high source side refrigerant is limited by the refrigerating capacity.

From the above, examples of the high-side refrigerant capable of achieving both environmental load and performance include R32 single refrigerant or a mixed refrigerant of R32 and HFO refrigerant. In addition, a mixed refrigerant of HFO-1123, which has a high refrigeration capacity among HFOs, and another HFO refrigerant or R32 is also listed as a candidate. The reason why HFO-1123 is mixed with another HFO refrigerant or R32 is to suppress the disproportionation reaction. Here, the R32 single refrigerant or the mixed refrigerant of R32 and HFO refrigerant is considered to be an alternative to the R410A refrigerant having similar characteristics, but the temperature after compression is higher than that of R410A. When a high-pressure shell type compressor is used as the high-end compressor 210, the temperature of the refrigerating machine oil further rises, so that the kinematic viscosity is further lowered. Therefore, also for the high-end compressor 210, the use of a low-pressure shell type compressor can prevent a decrease in the kinematic viscosity of the refrigeration oil and can improve the reliability of the bearing.

In Embodiment 1 described above, the dual refrigeration apparatus has been described, but it can be applied as a compressor of an apparatus using a refrigeration cycle (heat pump cycle) such as an air conditioner or a hot water supply apparatus. Moreover, although it was set as two elements, it is applicable also to the compressor of the multi-component refrigeration cycle apparatus comprised with a refrigerant circuit of three or more stages. Further, the present invention can also be applied to a compressor of a normal refrigerant circuit that is not a multistage configuration.

1 fixed scroll, 1a discharge port, 1b first spiral body, 1c first base plate, 2 swing scroll, 2b second spiral body, 2c second base plate, 2d concave bearing, 3 frame, 3a bearing part, 4 crank Shaft, 4a Eccentric pin part, 5 Suction pipe, 6 Rotor, 7 Stator, 8 Shell, 9 Compression chamber, 10 Valve presser, 11 Valve, 12 Oil reservoir, 13 Discharge pipe, 15 High pressure space, 16 Subframe, 16a Sub bearing 20 Oldham ring, 21 Oil pump, 22 Oil circuit, 35 Compression mechanism, 36 Drive mechanism, 50 Compressor, 100 Low-source refrigeration cycle, 110 Low-source compressor, 120 Low-source condenser, 130 Low-source Side expansion valve, 140 Low side evaporator, 200 High side refrigeration cycle, 210 High side compressor, 220 High side condensation , 230 high-stage-side expansion valve, 240 high-stage-side evaporator, 300 cascade condenser.

Claims (6)

A compression mechanism provided in the sealed container for compressing the refrigerant having carbon dioxide;
A shaft for applying a rotational force to the compressor mechanism,
A bearing for holding the shaft;
An oil pump for supplying refrigeration oil to the bearing,
The displacement amount Vst [cc / rev] of the refrigerant in the compression mechanism section satisfies 20 ≦ Vst ≦ 35 [cc / rev],
Esters having a kinematic viscosity ν [mm ² / s] at 40 [° C.] satisfying 480 / (6.5-0.13 × Vst) <ν <300 [mm ² / s] and having a viscosity index of 80 to 200 A compressor using oil as the refrigerating machine oil. The compressor according to claim 1, wherein the inside of the sealed container is a low-pressure side refrigerant atmosphere sucked. 3. The compressor according to claim 1, wherein the compressor is a scroll type compressor in which a compression chamber is formed by combining a fixed scroll and an orbiting scroll. A high-source refrigeration cycle that forms a high-side refrigerant circuit that circulates refrigerant by pipe-connecting the high-side compressor, the high-side condenser, the high-side decompressor, and the high-side evaporator,
A low-source refrigeration cycle that forms a low-source-side refrigerant circuit that circulates refrigerant by pipe-connecting a low-source-side compressor, a low-source-side condenser, a low-source-side decompressor and a low-source-side evaporator
A cascade condenser configured by the high-side evaporator and the low-side condenser, and performing heat exchange between the refrigerant flowing through the high-side refrigerant circuit and the refrigerant flowing through the low-side refrigerant circuit. ,
The refrigeration cycle apparatus using the compressor according to any one of claims 1 to 3 as at least one of the high-side compressor and the low-side compressor. 5. The carbon dioxide is used as a low-side refrigerant that circulates in the low-side refrigerant circuit, and R32 single refrigerant or a mixed refrigerant of R32 and HFO refrigerant is used as the high-side refrigerant that circulates in the high-side refrigerant circuit. Refrigeration cycle equipment. 5. The carbon dioxide is used as a low-side refrigerant that circulates in the low-side refrigerant circuit, and a mixed refrigerant containing HFO-1123 (trifluoroethylene) is used as the high-side refrigerant that circulates in the high-side refrigerant circuit. Refrigeration cycle equipment.

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