JP2008121626A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the increase in power consumption of a compressor by polyalkylene glycol in a refrigeration device with low environmental load using carbon dioxide as refrigerant. <P>SOLUTION: A refrigerant having GWP of 150 or less and an ester oil having a kinematic viscosity at 40°C of 20-200 mm<SP>2</SP>/s and a viscosity index of 20-140 are used. According to this, since the high-pressure viscosity of the ester oil enhances lubricity, the viscosity can be reduced to reduce the power loss by viscosity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compressor used in a refrigeration apparatus with a low environmental load.

  Conventionally, this type of compressor is disclosed in Patent Document 1.

FIG. 2 is a conceptual diagram showing a refrigeration circuit of the refrigeration apparatus described in Patent Document 1. As shown in FIG. 2, a refrigeration apparatus that circulates carbon dioxide as a refrigerant in a refrigeration circuit including a compressor 30, a radiator 31, an expansion mechanism 32, and an evaporator 33, and has a viscosity as refrigeration oil used for the compressor 30. A polyalkylene glycol refrigerating machine oil having a volume resistivity of 108 Ω · cm or more at 40 ° C. and a pour point of −30 ° C. or less when carbon dioxide is saturated and dissolved is obtained.
Japanese Patent No. 3600108

  In the conventional configuration, the refrigerating machine oil is surely returned to the compressor 30 and can be prevented from being seized, but the polyalkylene glycol has a helical molecular structure, so the molecules are easy to extend, The sliding part with a high surface pressure may cause the oil film to be cut off, and a refrigeration oil having a high viscosity must be employed to prevent this. As a result, the power consumption of the compressor 30 increases, and its suppression is a problem.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a highly efficient compressor for a low GWP refrigerant.

In order to solve the conventional problems, the compressor of the present invention uses a refrigerant having a GWP of 150 or less and an ether oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s and a viscosity index of 20 to 140. Is.

  Thereby, the high-pressure viscosity of the ether oil enhances the lubricity, and a lubricating oil having a lower kinematic viscosity at 40 ° C. can be used. As a result, it is possible to reduce power loss due to viscosity generated in a sliding portion such as a bearing.

  The compressor of the present invention is for a low GWP refrigerant with a small environmental load, and can improve its efficiency.

The first invention uses a refrigerant having a GWP of 150 or less and an ether oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s and a viscosity index of 20 to 140, thereby enhancing the lubricity of the lubricating oil. As a result, power loss in sliding parts such as bearings can be reduced.

  In the second invention, in particular, by using carbon dioxide as the refrigerant of the first invention, the GWP of the refrigerant becomes 1.0, and the environmental load can be minimized.

In the third aspect of the invention, in particular, the refrigerant of the first aspect of the invention is a mixed refrigerant. By providing a difference in the polarities of the constituent refrigerants, the pressure can be adjusted, and the refrigerant having a large polarity is converted into ether oil. It will dissolve well, making it possible to reduce the cost of the compressor and favorably returning the ether oil from the evaporator to the compressor.

  In the fourth aspect of the invention, in particular, since one of the constituent refrigerants in the mixed refrigerant of the second aspect of the invention is made incompatible with ether oil, the refrigerant that dissolves in ether oil is limited, and the performance of the compressor Can be stabilized.

  In the fifth invention, in particular, the ether oil of the first invention does not contain oxygen in the main chain, and the lubricity is further enhanced by the molecular structure having a small twist and the antiwear agent can be removed. The contamination resistance of the machine can be improved.

  In the sixth aspect of the invention, in particular, by providing an injection mechanism in the compression mechanism portion in the compressor of the first aspect of the invention, the heat absorption capability of the evaporator is improved, and the efficiency of the refrigeration apparatus can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a first embodiment of the present invention. This embodiment is a case of a scroll compressor for a refrigeration apparatus, and FIG.

  In FIG. 1, 1 is a scroll compressor, 2 is a condenser, 3 is a first pressure reducing device, 4 is a gas-liquid separator, 5 is a second pressure reducing device, and 6 is an evaporator, which are sequentially connected. Constitutes the refrigeration cycle.

  Reference numeral 7 denotes an airtight container, in which an electric motor 8 and a compression mechanism 9 are arranged. The compression mechanism 9 includes a crankshaft 10 driven by an electric motor 8, a turning scroll 11, a fixed scroll 12, and an Oldham ring 13 that supports the turning scroll 11 to make a turning motion without rotating with respect to the fixed scroll 12. And the frame 14 for supporting the Oldham ring 13 so as to be movable for the support.

  The crankshaft 10 is supported by bearings 16 and 17 of the frame 14. A shaft 11 a of the orbiting scroll 11 is supported by a bearing 10 c provided on the crank portion 10 a of the crankshaft 10, and is engaged with the fixed scroll 12 to form a compression chamber 15. In addition, 18 is an inlet and 19 is an outlet.

  Reference numeral 16 of the sealed container 7 is a suction pipe connected to the evaporator 6, and 23 is a discharge pipe connected to the condenser 2. An injection tube 24 connects the gas-liquid separator 4 and the compression chamber 15 of the compression mechanism 9 via the sealed container 7.

  An oil sump 20 is provided in the lowermost part of the sealed container 7, and the lubricating oil 21 in the oil sump 20 is supplied to the lubrication target portion through the oil supply passage 10 b of the crankshaft 10, but the bearing 16 has an oil supply hole. 10d.

The lubricating oil 21 is an ether oil and does not contain oxygen in the main chain, that is, has no C—O—C bond, and has a molecular structure with a small twist. Kinematic viscosity at 40 ° C. of ether oil is 20 to 200 mm ² / s, is less than 20 mm ² / s is insufficient lubricity, the power loss increases exceeds 200 mm ² / s. The viscosity index is 20 to 140. If it is less than 20, the kinematic viscosity at a high temperature, that is, 100 ° C. is insufficient, and if it exceeds 140, the high-pressure viscosity is insufficient. The viscosity index is preferably 40 to 120.

  The refrigerant is carbon dioxide having a GWP of 1.0.

  About the scroll compressor 1 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the crankshaft 10 is rotated by being driven by the electric motor 8, the orbiting scroll 11 is orbited through the Oldham ring 13 and sucks the gas refrigerant from the suction pipe 22 into the suction port 18. In the compression chamber 15, the gas refrigerant is compressed by reducing its volume while being moved from the outer peripheral side leading to the suction port 18 to the inner peripheral side leading to the discharge port 19, and discharged from the discharge port 19 into the sealed container 7. The high-temperature and high-pressure gas refrigerant is supplied to the refrigeration cycle from the discharge pipe 23, but is liquefied by the condenser 2, depressurized by the first decompression device 3, becomes two-phase, and reaches the gas-liquid separator 4. Here, the refrigerant is separated, and the liquid refrigerant is further decompressed by the second decompression device 5, gasified by the evaporator 6, and reaches the suction pipe 22 of the scroll compressor 1. On the other hand, the gas refrigerant separated by the gas-liquid separator is introduced into the compression chamber 15 of the compression mechanism 9 via the injection pipe 24 and compressed together with the suction gas refrigerant.

  Since the ether oil exhibits high lubricity in the sliding portions of the crankshaft 10, the Oldham ring 13 and the orbiting scroll 11 due to its high high-pressure viscosity, those having a low kinematic viscosity at 40 ° C. can be used. As a result, power loss due to viscosity at each sliding portion can be suppressed, and the efficiency of the scroll compressor 1 can be increased.

  Carbon dioxide has a GWP of 1.0, which not only minimizes the environmental burden, but also has relatively good compatibility with ether oil, so it does not separate into two layers in the evaporator, so high heat transfer performance in the evaporator Can also be obtained. As a result, the evaporator can be reduced in size.

  In addition, since ether oil has a molecular structure with small twist, its high-pressure viscosity is further increased and lubricity is enhanced. As a result, since it is not necessary to add a highly reactive antiwear agent, the stability of the ether oil is increased and the contamination resistance of the refrigeration apparatus as well as the scroll compressor 1 can be improved.

  Moreover, since the refrigeration effect is increased by the liquid refrigerant separated by the gas-liquid separator 4, the heat absorption capability of the evaporator 6 is improved. However, the heat transfer performance of the evaporator 6 is improved by the compatibility of ether oil and carbon dioxide. For this reason, the efficiency of the refrigeration apparatus can be improved because the heat absorption capacity of the evaporator is increased.

  Further, by using two types of refrigerant as the refrigerant, the operating pressure, particularly the pressure on the high-pressure side can be adjusted moderately, but the polarity of the constituent refrigerant, particularly the dipole moment, is 0.5 debye or more, preferably 1. By providing a difference of 0 debye or more, a refrigerant having a large polarity is well dissolved in ether oil, so that the return of ether oil from the evaporator 6 to the scroll compressor 1 can be improved.

  Also, by making one of the constituent refrigerants of the two types of mixed refrigerants incompatible with ether oil, only one type of refrigerant is dissolved in ether oil, so the performance of the compressor can be stabilized. .

As described above, the compressor according to the present invention enhances lubricity by the high-pressure viscosity of ether oil to reduce power loss in the sliding portion, and can be applied to hot water supply equipment and automobile air conditioners.

The longitudinal cross-sectional view of the scroll compressor in Embodiment 1 of this invention Conceptual diagram showing a refrigeration circuit of a conventional refrigeration system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scroll compressor 9 Compression mechanism 10 Crankshaft 11 Orbiting scroll 13 Oldham ring 21 Lubricating oil

Claims (6)

A compressor using a refrigerant having a GWP of 150 or less and an ether oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s and a viscosity index of 20 to 140. The compressor according to claim 1, wherein the refrigerant is carbon dioxide. The compressor according to claim 1, wherein the refrigerant is a mixed refrigerant, and a difference is provided in the polarity of the constituent refrigerant. The compressor according to claim 2, wherein one of the refrigerants constituting the mixed refrigerant is hardly compatible with ether oil. The compressor according to claim 1, wherein the ether oil does not contain oxygen in the main chain. The compressor according to claim 1, wherein an injection mechanism is provided in the compression mechanism section.

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