JP2008121625A - 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 50-200 mm<SP>2</SP>/s and a viscosity index of 80-200 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 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.

  As a result, the high-pressure viscosity of the ester 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 ester oil having a kinematic viscosity at 40 ° C. of 50 to 200 mm ² / s and a viscosity index of 80 to 200, 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 invention, in particular, the refrigerant of the first invention is a mixed refrigerant. By providing a difference in the polarity of the constituent refrigerant, the pressure can be adjusted, and the refrigerant having a large polarity can be used as the ester oil. It will dissolve well, the cost of the compressor can be reduced, and the return of ester oil from the evaporator to the compressor can be improved.

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

  In the fifth invention, in particular, the ester oil of the first invention uses a fatty acid having a branch in the vicinity of the terminal, so that the stability of the ester oil is improved and the contamination resistance of the compressor can be improved. .

  In the sixth aspect of the invention, in particular, the ester oil of the first aspect of the present invention is a mixed oil having a different oxygen content, so that the antiwear agent becomes effective and the wear resistance of the sliding member can be improved.

  In the seventh aspect of the invention, in particular, by providing the injection mechanism in the compression mechanism portion of 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 ester oil, and is composed of a tetravalent alcohol such as pentaerythritol and a fatty acid having a relatively long branch near the end. This fatty acid sterically covers and protects the oxygen double bond.

Kinematic viscosity at 40 ° C. of the ester oil is 50 to 200 mm ² / s, is less than 50 mm ² / s is insufficient lubricity, the power loss increases exceeds 200 mm ² / s. The viscosity index is 80-200 and is related to fatty acids. If it is less than 80, the ability to protect double bonds of oxygen by fatty acids is reduced, and if it exceeds 200, the high-pressure viscosity is reduced. The viscosity index is preferably 100 to 180.

  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.

  The ester 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, so that it can be used having a low kinematic viscosity at 40 ° C. 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 ester 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.

  Further, since the fatty acid having a branch near the terminal sterically protects the double bond of oxygen, the stability of the ester oil is increased, so that not only the scroll compressor 1 but also the refrigeration apparatus can be improved in contamination resistance.

  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 ester 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 mixed oil having different oxygen contents as the ester oil, the antiwear agent is likely to be effective on the sliding surface of the sliding member, so that the operable load of the scroll compressor 1 can be 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 the ester oil, so that the return of the ester oil from the evaporator 6 to the scroll compressor 1 can be improved.

  In addition, by making one of the constituent refrigerants in the two types of refrigerant mixture incompatible with ester oil, only one type of refrigerant is dissolved in the ester oil, so the performance of the compressor is stabilized. it can.

  As described above, the compressor according to the present invention enhances the lubricity by the high-pressure viscosity of the ester oil to reduce the power loss in the sliding portion, and can be applied to hot water supply facilities 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 (7)

A compressor using a refrigerant having a GWP of 150 or less and an ester oil having a kinematic viscosity at 40 ° C. of 50 to 200 mm ² / s and a viscosity index of 80 to 200. 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 constituent refrigerants of the mixed refrigerant is hardly compatible with the ester oil. The compressor according to claim 1, wherein the ester oil uses a fatty acid having a branch near the end. The compressor according to claim 1, wherein the ester oil is a mixed oil having different oxygen contents. The compressor according to claim 1, wherein an injection mechanism is provided in the compression mechanism section.

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