JP2017089982A - Freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezer capable of suppressing reduction of refrigeration oil stored inside a compressor.SOLUTION: An air conditioner 120 includes a compressor 112 and a refrigerant circuit 110. The compressor 112 compresses refrigerant. In the refrigerant circuit 110, refrigerant and fluid containing refrigeration oil are sealed and the refrigerant is circulated by the compressor 112 to perform refrigeration cycle. To the fluid sealed in the refrigerant circuit 110, an amount of defoaming agent exceeding a limit dissolution amount is added. The limit dissolution amount is a maximum amount of defoaming agent capable of being dissolved in the refrigerant oil contained in the fluid sealed in the refrigerant circuit 110, under room temperature and atmospheric pressure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigeration apparatus.

  The air conditioner includes a compressor for compressing the refrigerant and supplying the refrigerant to the refrigerant circuit. When the compressor is stopped for a long time, the refrigerant gradually dissolves in the refrigeration oil stored in the oil reservoir at the bottom of the compressor. When the compressor is started in this state, the refrigerant dissolved in the refrigeration oil is heated and evaporated all at once, and a foam layer of the refrigeration oil is formed on the liquid level of the refrigeration oil stored in the oil reservoir. . Then, together with the compressed refrigerant gas, the refrigerating machine oil bubbles are discharged to the refrigerant circuit outside the compressor, and the refrigerating machine oil stored in the oil reservoir is reduced. As a result, the refrigerating machine oil is not sufficiently supplied to the sliding portion inside the compressor, and there is a risk that problems such as seizure will occur.

  Conventionally, as described in Patent Document 1 (Japanese Patent Laid-Open No. 59-128986) and Patent Document 2 (Japanese Patent Laid-Open No. 2010-210208), it is considered that bubbles of refrigeration oil are generated when the compressor is started. A crankcase heater is used to prevent this. The crankcase heater is an electric heater attached to the oil reservoir of the compressor. Even when the compressor has been stopped for a long time, the refrigerant that is dissolved in the refrigeration machine oil stored in the oil reservoir is evaporated by heating the oil reservoir with a crankcase heater before the compressor is started. This can reduce the generation of bubbles in the refrigeration oil when the compressor is started.

  However, in small stores and the like, the breaker may be completely dropped outside business hours, and the crankcase heater is not energized during that time. In addition, when the outside air temperature is low, such as in winter, the amount of refrigerant that dissolves in the refrigerating machine oil when the compressor is stopped increases. Therefore, even if the compressor is provided with a crankcase heater, depending on the operation status of the air conditioner, bubbles of refrigeration oil may be generated when the compressor is started. In addition, when the oil reservoir is heated by the crankcase heater before the compressor is started, it is preferable to stop the compressor until the refrigeration oil stored in the oil reservoir reaches a predetermined temperature. Therefore, when a crankcase heater is used, it may take time to start the compressor.

  The objective of this invention is providing the refrigeration apparatus which can suppress the reduction | decrease of the refrigerating machine oil stored inside a compressor.

  The refrigeration apparatus according to the first aspect of the present invention includes a compressor and a refrigerant circuit. The compressor compresses the refrigerant. The refrigerant circuit encloses a fluid containing refrigerant and refrigeration oil, and performs a refrigeration cycle by circulating the refrigerant using a compressor. An antifoaming agent in an amount exceeding the limit dissolution amount is added to the fluid sealed in the refrigerant circuit. The limit dissolution amount is the maximum amount of the antifoaming agent that can be dissolved in the refrigerating machine oil contained in the fluid sealed in the refrigerant circuit at room temperature and atmospheric pressure.

  In this refrigeration system, the amount of antifoaming agent exceeding the limit dissolution amount is added to the fluid sealed in the refrigerant circuit, so that it is generated at the level of the refrigeration oil stored in the oil reservoir when the compressor is started. It is possible to greatly reduce the foam to be used. Therefore, at the time of starting the compressor, it is possible to suppress the bubbles of the refrigerating machine oil from being discharged to the refrigerant circuit outside the compressor together with the compressed refrigerant gas. Therefore, this refrigeration apparatus can suppress a decrease in refrigeration oil stored in the compressor.

  The refrigeration apparatus according to the second aspect of the present invention is the refrigeration apparatus according to the first aspect, and the defoamer that dissolves in the refrigerant is added to the fluid sealed in the refrigerant circuit.

  In this refrigeration apparatus, since an antifoaming agent that dissolves in the refrigerant is used, the antifoaming agent discharged to the outside of the compressor returns to the compressor in a state of being dissolved in the refrigerant. Therefore, it is possible to prevent the phenomenon that the defoaming agent in the compressor is insufficient and the bubbles generated on the liquid surface of the refrigerating machine oil at the time of starting the compressor are not sufficiently reduced.

  The refrigeration apparatus according to the third aspect of the present invention is the refrigeration apparatus according to the second aspect, and the antifoaming agent contains fluorosilicone as a main component.

  A refrigeration apparatus according to a fourth aspect of the present invention is the refrigeration apparatus according to any one of the first to third aspects, wherein the refrigerant contains fluorine.

  The refrigerating apparatus according to the present invention can suppress a decrease in refrigerating machine oil stored in the compressor.

It is a block diagram of the refrigerant circuit of the air conditioning apparatus which concerns on embodiment of this invention. It is a longitudinal cross-sectional view of the compressor of a refrigerant circuit. It is a block diagram of the pressure vessel used in the test of an Example. It is a figure showing the state before the heating with a heater. It is a block diagram of the pressure vessel used in the test of an Example. It is a figure showing the state after the heating with a heater. It is a graph showing the relationship between the foaming reduction rate measured by the test of the Example, and the addition amount of an antifoamer.

(1) Configuration of Air Conditioner An air conditioner 120 that is a refrigeration apparatus according to an embodiment of the present invention will be described. The air conditioner 120 includes a refrigerant circuit 110. The refrigerant circuit 110 is filled with refrigerant and performs a refrigeration cycle. FIG. 1 is a configuration diagram of the refrigerant circuit 110. The refrigerant circuit 110 mainly includes a compressor 112, a four-way switching valve 113, an outdoor heat exchanger 114, an expansion mechanism 115, and an indoor heat exchanger 116. In FIG. 1, the solid arrow represents the refrigerant flow during the cooling operation, and the dotted arrow represents the refrigerant flow during the heating operation. The air conditioner 120 includes one indoor heat exchanger 116, but may include a plurality of indoor heat exchangers 116.

  The refrigeration cycle performed by the refrigerant circuit 110 during the cooling operation will be described. First, the compressor 112 compresses the low-pressure gas refrigerant and discharges the high-pressure gas refrigerant. The refrigerant discharged from the compressor 112 passes through the four-way switching valve 113 and is supplied to the outdoor heat exchanger 114. The outdoor heat exchanger 114 condenses the high-pressure gas refrigerant and discharges the high-pressure liquid refrigerant. The refrigerant discharged from the outdoor heat exchanger 114 passes through the expansion valve of the expansion mechanism 115 to become a low-pressure gas-liquid mixed refrigerant and is supplied to the indoor heat exchanger 116. The indoor heat exchanger 116 evaporates the low-pressure gas-liquid mixed refrigerant and discharges the low-pressure gas refrigerant. The refrigerant discharged from the indoor heat exchanger 116 is supplied to the compressor 112.

  During the cooling operation, the outdoor heat exchanger 114 functions as a condenser, and the indoor heat exchanger 116 functions as an evaporator. That is, the room is cooled by the latent heat of vaporization of the refrigerant generated in the indoor heat exchanger 116. On the other hand, during the heating operation, by switching the four-way switching valve 113, the outdoor heat exchanger 114 functions as an evaporator, and the indoor heat exchanger 116 functions as a condenser. That is, the room is heated by the condensation latent heat of the refrigerant generated in the outdoor heat exchanger 114.

In the present embodiment, a refrigerant containing fluorine is used as the refrigerant circulating in the refrigerant circuit 110 of the air conditioner 120. The refrigerant filled in the refrigerant circuit 110 is, for example, an R32 refrigerant. The R32 refrigerant is a refrigerant containing R32 represented by the molecular formula CH ₂ F ₂ . Specifically, the R32 refrigerant is an R32 single refrigerant or a mixed refrigerant containing R32. The mixed refrigerant containing R32 is, for example, a mixed refrigerant such as R410A and R407C.

(2) Configuration of Compressor Next, the compressor 112 constituting the refrigerant circuit 110 will be described. In the present embodiment, the compressor 112 is a scroll compressor that compresses refrigerant using two scroll members having spiral-shaped wraps that mesh with each other. The compressor 112 is a high-low pressure dome type scroll compressor.

  FIG. 2 is a longitudinal sectional view of the compressor 112. The compressor 112 mainly includes a casing 10, a compression mechanism 15, a housing 23, an Oldham coupling 39, a drive motor 16, a lower bearing 60, a crankshaft 17, a suction pipe 19, and a discharge pipe 20. Composed.

(2-1) Casing The casing 10 includes a cylindrical body casing portion 11, a bowl-shaped upper wall section 12, and a bowl-shaped bottom wall section 13. The upper wall portion 12 is welded to the upper end portion of the trunk portion casing portion 11 in an airtight manner. The bottom wall portion 13 is welded to the lower end portion of the body casing portion 11 in an airtight manner. The casing 10 is formed of a rigid member that is unlikely to be deformed or damaged when pressure or temperature changes inside or outside the casing 10. The casing 10 is installed such that the cylindrical axial direction of the body casing portion 11 is along the vertical direction.

  Inside the casing 10, a compression mechanism 15, a housing 23 disposed below the compression mechanism 15, a drive motor 16 disposed below the housing 23, and a crankshaft 17 disposed to extend in the vertical direction. Etc. are housed. A suction pipe 19 and a discharge pipe 20 are welded to the casing 10 in an airtight manner.

  An oil sump space 10 a in which refrigeration oil is stored is formed at the bottom of the casing 10. The refrigerating machine oil is used to keep the lubricity of the sliding portion such as the compression mechanism 15 during the operation of the compressor 112. The refrigerating machine oil is enclosed in the refrigerant circuit 110 together with the refrigerant.

(2-2) Compression mechanism The compression mechanism 15 is accommodated in the casing 10, sucks and compresses the low-temperature and low-pressure refrigerant gas, and discharges the high-temperature and high-pressure refrigerant gas (hereinafter referred to as "compressed refrigerant"). . The compression mechanism 15 is mainly composed of a fixed scroll 24 and a movable scroll 26. The fixed scroll 24 is fixed to the housing 23. The movable scroll 26 performs a revolving motion with respect to the fixed scroll 24.

(2-2-1) Fixed Scroll The fixed scroll 24 includes a first end plate 24a and a spiral first wrap 24b formed upright on the upper surface of the first end plate 24a. A main suction hole 24c is formed in the first end plate 24a. The main suction hole 24c is a space that connects the suction pipe 19 and a compression chamber 40 described later. The main suction hole 24 c forms a suction space for introducing a low-temperature and low-pressure refrigerant gas from the suction pipe 19 into the compression chamber 40.

  A discharge hole 41 is formed in the central portion of the first end plate 24a, and an enlarged recess 42 communicating with the discharge hole 41 is formed on the upper surface of the first end plate 24a. The enlarged recess 42 is a space recessed in the upper surface of the first end plate 24a. A lid 44 is fixed to the upper surface of the fixed scroll 24 with bolts 44 a so as to close the enlarged recess 42. The fixed scroll 24 and the lid 44 are tightly sealed through a gasket (not shown). A muffler space 45 that silences the operation sound of the compression mechanism 15 is formed by covering the enlarged recess 42 with the lid 44. The fixed scroll 24 is formed with a first compressed refrigerant channel 46 that communicates with the muffler space 45 and opens on the lower surface of the fixed scroll 24. An oil groove 24e is formed on the lower surface of the first end plate 24a.

(2-2-2) Movable Scroll The movable scroll 26 includes a disk-shaped second end plate 26a and a spiral-shaped second wrap 26b formed upright on the upper surface of the second end plate 26a. An upper end bearing 26c is formed at the center of the lower surface of the second end plate 26a. The movable scroll 26 has an oil supply hole 63 formed therein. The oil supply pore 63 communicates the outer peripheral portion of the upper surface of the second end plate 26a and the space inside the upper end bearing 26c.

  The fixed scroll 24 and the movable scroll 26 are surrounded by the first end plate 24a, the first wrap 24b, the second end plate 26a, and the second wrap 26b when the first wrap 24b and the second wrap 26b are engaged with each other. A compression chamber 40 that is a space is formed. The volume of the compression chamber 40 is gradually reduced by the revolving motion of the movable scroll 26, whereby the refrigerant in the compression chamber 40 is compressed. During the revolution of the movable scroll 26, the lower surfaces of the first end plate 24 a and the first wrap 24 b of the fixed scroll 24 slide with the upper surfaces of the second end plate 26 a and the second wrap 26 b of the movable scroll 26. Hereinafter, the surface of the fixed scroll 24 that slides with the movable scroll 26 is referred to as a thrust sliding surface 24d. The oil groove 24e of the fixed scroll 24 is formed on the lower surface of the first end plate 24a so as to fit in the thrust sliding surface 24d.

(2-3) Housing The housing 23 is disposed below the compression mechanism 15. The outer peripheral surface of the housing 23 is joined to the inner peripheral surface of the body casing portion 11 in an airtight manner. Thereby, the internal space of the casing 10 is partitioned into a high-pressure space S <b> 1 below the housing 23 and an upper space S <b> 2 that is a space above the housing 23. The housing 23 mounts a fixed scroll 24 and holds a movable scroll 26 together with the fixed scroll 24. A second compressed refrigerant channel 48 is formed through the outer periphery of the housing 23 in the vertical direction. The second compressed refrigerant channel 48 communicates with the first compressed refrigerant channel 46 on the upper surface of the housing 23, and communicates with the high-pressure space S <b> 1 on the lower surface of the housing 23.

  A crank chamber S <b> 3 is recessed in the upper surface of the housing 23. A housing through hole 31 is formed in the housing 23. The housing through hole 31 penetrates the housing 23 in the vertical direction from the center of the bottom surface of the crank chamber S3 to the center of the lower surface of the housing 23. Hereinafter, a portion that is a part of the housing 23 and in which the housing through hole 31 is formed is referred to as an upper bearing 32. The housing 23 is formed with an oil return passage 23a that connects the high-pressure space S1 near the inner surface of the casing 10 and the crank chamber S3.

(2-4) Oldham Joint The Oldham Joint 39 is an annular member installed between the movable scroll 26 and the housing 23. The Oldham coupling 39 is a member for preventing rotation of the orbiting scroll 26 that is revolving.

(2-5) Drive Motor The drive motor 16 is a brushless DC motor disposed below the housing 23. The drive motor 16 mainly includes a stator 51 that is fixed to the inner surface of the casing 10 and a rotor 52 that is disposed with an air gap provided inside the stator 51.

  The outer peripheral surface of the stator 51 is provided with a plurality of core cut portions that are notched from the upper end surface of the stator 51 to the lower end surface and at a predetermined interval in the circumferential direction. The core cut portion forms a motor cooling passage 55 that extends in the vertical direction between the body casing portion 11 and the stator 51.

  The rotor 52 is connected to the crankshaft 17 that passes through the center of rotation in the vertical direction. The rotor 52 is connected to the compression mechanism 15 via the crankshaft 17.

(2-6) Lower Bearing The lower bearing 60 is disposed below the drive motor 16. The outer peripheral surface of the lower bearing 60 is joined to the inner surface of the casing 10 in an airtight manner. The lower bearing 60 supports the crankshaft 17. An oil separation plate 65 is attached to the upper end of the lower bearing 60. The oil separation plate 65 is a flat plate member accommodated in the casing 10. The oil separation plate 65 is fixed to the upper end surface of the lower bearing 60.

(2-7) Crankshaft The crankshaft 17 is accommodated in the casing 10. The crankshaft 17 is arranged so that its axial direction is along the vertical direction. The crankshaft 17 has a shape in which the axial center of the upper end portion is slightly eccentric with respect to the axial center of the portion excluding the upper end portion. The crankshaft 17 has a balance weight 18. The balance weight 18 is fixed in close contact with the crankshaft 17 at a height position below the housing 23 and above the drive motor 16.

  The crankshaft 17 passes through the rotation center of the rotor 52 in the vertical direction and is connected to the rotor 52. The crankshaft 17 is connected to the movable scroll 26 by fitting the upper end of the crankshaft 17 into the upper end bearing 26c. The crankshaft 17 is supported by the upper bearing 32 and the lower bearing 60 of the housing 23.

  The crankshaft 17 has a main oil supply passage 61 extending in the axial direction thereof. The upper end of the main oil supply passage 61 communicates with an oil chamber 67 formed by the upper end surface of the crankshaft 17 and the second main surface 26e. The oil chamber 67 communicates with the thrust sliding surface 24d and the oil groove 24e via the oil supply hole 63 of the second end plate 26a, and finally communicates with the low pressure space S2 via the compression chamber 40. The lower end of the main oil supply passage 61 communicates with the oil sump space 10a.

  The crankshaft 17 includes a first sub oil supply path 61 a, a second sub oil supply path 61 b, and a third sub oil supply path 61 c that branch from the main oil supply path 61. The first sub oil supply path 61a, the second sub oil supply path 61b, and the third sub oil supply path 61c extend in the horizontal direction. The first sub oil supply passage 61 a is open to the sliding surface between the crankshaft 17 and the upper end bearing 26 c of the movable scroll 26. The second sub oil supply passage 61 b is open to the sliding surface between the crankshaft 17 and the upper bearing 32 (upper bearing metal 33) of the housing 23. The third sub oil supply passage 61 c is open on the sliding surface between the crankshaft 17 and the lower bearing 60.

(2-8) Suction Pipe The suction pipe 19 is a pipe for introducing the refrigerant of the refrigerant circuit from the outside of the casing 10 to the compression mechanism 15. The suction pipe 19 is fitted into the upper wall portion 12 of the casing 10 in an airtight manner. The suction pipe 19 penetrates the upper space S2 in the vertical direction. The inner end of the suction pipe 19 is fitted in the main suction hole 24 c of the fixed scroll 24. The inner end of the suction pipe 19 is the end of the suction pipe 19 in the internal space of the casing 10.

(2-9) Discharge Pipe The discharge pipe 20 is a pipe for discharging the compressed refrigerant from the high-pressure space S1 to the outside of the casing 10. The discharge pipe 20 is fitted in the body casing part 11 of the casing 10 in an airtight manner. The discharge pipe 20 penetrates the high-pressure space S1 in the horizontal direction. The opening 20 a of the discharge pipe 20 in the casing 10 is located in the vicinity of the housing 23.

(3) Composition of refrigeration oil Next, the refrigeration oil enclosed in the refrigerant circuit 110 will be described. The refrigerating machine oil is a lubricating oil used for preventing wear and seizure in sliding parts such as the compressor 112. The refrigerating machine oil mainly comprises a base oil, an acid scavenger, an extreme pressure agent, an antioxidant and an antifoaming agent.

  As the base oil, mineral oil or synthetic oil is used. As the base oil, one having good compatibility with the R32 refrigerant used in the air conditioner 120 is appropriately selected. The mineral oil is, for example, a naphthenic mineral oil or a paraffinic mineral oil. Synthetic oils are, for example, ester compounds, ether compounds, poly α-olefins, and alkylbenzenes. Specific examples of the synthetic oil include polyvinyl ether, polyol ester, polyalkylene glycol and the like. In this embodiment, it is preferable to use synthetic oils such as polyvinyl ether and polyol ester as the base oil. In addition, as a base oil, the mixture which combined 2 or more types of said mineral oil or synthetic oil may be used.

  The acid scavenger is an additive used for suppressing deterioration of the refrigerating machine oil due to an acid by reacting with an acid such as hydrofluoric acid generated by the decomposition of the R32 refrigerant. The acid scavenger is, for example, an epoxy compound, a carbodiimide compound, or a tempen compound. Specific examples of the acid scavenger include 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, epoxidized cyclohexyl carbinol, di (alkylphenyl) carbodiimide, β-pinene and the like.

  The extreme pressure agent is an additive used to improve the effect of preventing wear and seizure in the sliding portion of the compressor 112 and the like. Refrigerating machine oil prevents contact between the sliding members by forming an oil film between the surfaces of the members that slide on each other at the sliding portion. However, when a low-viscosity refrigerating machine oil such as polyvinyl ether is used and when the pressure applied to the sliding member is high, the sliding members easily come into contact with each other. The extreme pressure agent suppresses the occurrence of wear and seizure by forming a film by reacting with the surfaces of members that slide on each other at the sliding portion. Examples of the extreme pressure agent include phosphate ester, phosphite ester, thiophosphate, sulfide ester, sulfide, thiobisphenol, and the like. Specific examples of extreme pressure agents include tricresyl phosphate (TCP), triphenyl phosphate (TPP), triphenyl phosphorothioate (TPPT), amine, C11-14 side chain alkyl, monohexyl and dihexyl phosphate. TCP is adsorbed on the surface of the sliding member and decomposes to form a phosphate coating.

  Antioxidants are additives used to prevent the refrigeration machine oil from being oxidized. Specific examples of the antioxidant include zinc dithiophosphate, organic sulfur compound, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,2 Phenols such as' -methylenebis (4-methyl-6-tert-butylphenol), amine-based antioxidants such as phenyl-α-naphthylamine, N, N'-di-phenyl-p-phenylenediamine, N, N Examples include '-disalicylidene-1,2-diaminopropane.

  The antifoaming agent is an additive used for reducing the forming of the refrigerating machine oil that occurs when the compressor 112 is started. Antifoaming agents include silicone oil (dimethylpolysiloxane) and polymethacrylates.

  The purpose of adding the antifoaming agent and the effect of the antifoaming agent will be described. When the air conditioner 120 is turned off and the compressor 112 is stopped for a long time, the refrigerant remaining in the high-pressure space S1 and the like gradually dissolves in the refrigerating machine oil stored in the oil sump space 10a. As a result, a mixture of refrigerating machine oil and refrigerant is gradually generated in the oil sump space 10a. The oil concentration that is the concentration of the refrigerating machine oil in this mixture gradually decreases as the refrigerant dissolves in the refrigerating machine oil. When the compressor 112 is started in a state where the oil concentration of the mixture stored in the oil sump space 10a is low, the refrigerant dissolved in the refrigeration oil is heated and evaporated all at once, thereby generating refrigerant gas in the mixture. . The generated refrigerant gas may form a foam layer of the refrigerating machine oil on the liquid level of the refrigerating machine oil stored in the oil sump space 10a. At this time, the bubbles of the refrigerating machine oil are discharged together with the compressed refrigerant gas to the refrigerant circuit 110 outside the compressor 112, so that the refrigerating machine oil stored in the oil sump space 10a is reduced, and the liquid level of the refrigerating machine oil is reduced. May gradually decrease. As a result, the refrigerating machine oil is not sufficiently supplied to the sliding portion inside the compressor 112, and there is a possibility that problems such as seizure occur. The antifoaming agent added to the refrigerating machine oil suppresses the formation of forming when the compressor 112 is started, and the refrigerating machine oil bubbles are discharged to the refrigerant circuit 110 outside the compressor 112 together with the compressed refrigerant gas. To suppress that. Therefore, the antifoaming agent has an effect of suppressing a decrease in the liquid level of the refrigerating machine oil stored in the oil sump space 10a when the compressor 112 is started up and preventing occurrence of problems such as seizure of the sliding portion.

  In the present embodiment, an antifoaming agent in an amount exceeding the limit dissolution amount is added to the enclosing fluid encapsulated in the refrigerant circuit 110 and including the refrigerant and the refrigerating machine oil. The limit dissolution amount is the maximum amount of the antifoaming agent that can be dissolved in the refrigerating machine oil contained in the sealed fluid at normal temperature and atmospheric pressure. That is, the antifoaming agent obtained by subtracting the limit dissolution amount from the amount of the antifoaming agent added to the sealed fluid is not dissolved in the refrigerating machine oil contained in the sealed fluid.

  Moreover, it is preferable that the antifoamer added to the enclosed fluid in the refrigerant circuit 110 has a property of being dissolved in the refrigerant contained in the enclosed fluid. That is, it is preferable that at least a part of the antifoaming agent obtained by subtracting the limit dissolution amount from the amount of the antifoaming agent added to the sealed fluid is dissolved in the refrigerant contained in the sealed fluid.

  Moreover, it is preferable that an antifoamer has fluorosilicone as a main component.

(4) Features In the air conditioner 120 according to the present embodiment, the oil reservoir space 10a is activated when the compressor 112 is started by adding an antifoaming agent in an amount exceeding the limit dissolution amount to the sealed fluid in the refrigerant circuit 110. The foaming that is generated on the liquid surface of the refrigerating machine oil stored in can be greatly reduced. That is, the foaming at the time of starting of the compressor 112 is suppressed by adding an excessive antifoaming agent to the sealed fluid. For this reason, when the compressor 112 is started, the bubbles of the refrigerating machine oil are suppressed from being discharged to the refrigerant circuit 110 outside the compressor 112 together with the compressed refrigerant gas. Therefore, the air conditioning apparatus 120 can suppress a decrease in refrigerating machine oil stored in the compressor 112.

  In the air conditioner 120, an antifoaming agent that dissolves in the refrigerant contained in the sealed fluid in the refrigerant circuit 110 is used. Therefore, when the antifoaming agent that is not dissolved in the refrigerating machine oil is discharged to the refrigerant circuit 110 outside the compressor 112, the antifoaming agent can be dissolved in the refrigerant circulating in the refrigerant circuit 110. As a result, at least a part of the antifoaming agent discharged to the refrigerant circuit 110 flows through the refrigerant circuit 110 and is again sucked into the compressor 112 while being dissolved in the refrigerant. Thereby, since the antifoamer discharged from the compressor 112 is returned to the compressor 112, it is suppressed that the defoamer in the compressor 112 runs short. Therefore, the air conditioning apparatus 120 can suppress a phenomenon in which forming at the time of starting the compressor 112 is not sufficiently reduced due to a lack of the antifoaming agent in the compressor 112.

(5) Example The test which confirms the effect of the antifoamer added to the refrigerating machine oil enclosed with the refrigerant circuit 110 of the air conditioning apparatus 120 in this embodiment was done. Next, details and results of this test will be described.

  3 and 4 are configuration diagrams of the pressure vessel 200 used in this test. The pressure vessel 200 is a cylindrical vessel. The pressure vessel 200 is formed of a rigid member that is unlikely to be deformed or damaged when the internal pressure or temperature changes. The pressure vessel 200 is installed so that the axial direction of the cylindrical shape is along the vertical direction. Inside the pressure vessel 200, a rod-shaped heater 202 is installed. The heater 202 is installed such that its longitudinal direction is along the vertical direction.

  A liquid layer 204 and a gas layer 206 are formed in the internal space of the pressure vessel 200. The liquid layer 204 is composed of a mixture of refrigerant and refrigeration oil. The gas layer 206 is composed of a refrigerant gas contained in the liquid layer 204. The refrigerant is R32 alone. The refrigerating machine oil is polyvinyl ether. The limit dissolution amount of the antifoam added to the refrigerating machine oil is 50 ppm.

  The heater 202 is installed to heat the liquid layer 204. FIG. 3 is a diagram illustrating a state before the liquid layer 204 is heated by the heater 202. FIG. 4 is a diagram illustrating a state after the liquid layer 204 is heated by the heater 202. As shown in FIG. 4, after the liquid layer 204 is heated by the heater 202, a forming layer 208 that is a foam layer of refrigerating machine oil is formed at the boundary between the liquid layer 204 and the gas layer 206. As described above, the forming layer 208 is formed by heating the refrigerant dissolved in the refrigerating machine oil in the liquid layer 204 and evaporating it at once. Hereinafter, the dimension in the vertical direction of the forming layer 208 formed when the temperature of the liquid layer 204 is raised from 20 ° C. to 35 ° C. using the heater 202 is referred to as a forming height H.

  FIG. 5 is a graph showing the relationship between the forming reduction rate and the amount of antifoaming agent added for four types of antifoaming agents. FIG. 5 plots the measurement results of each antifoaming agent. The horizontal axis of FIG. 5 represents the addition amount (ppm) of an antifoamer. The vertical axis in FIG. 5 represents the forming reduction rate (%). The forming reduction rate represents the reduction rate of the forming height H by the antifoaming agent. The higher the forming reduction rate, the greater the effect of the antifoaming agent. Specifically, the forming height formed when the liquid layer 204 made of a mixture of refrigerating machine oil not containing an antifoaming agent and a refrigerant is heated by the heater 202 is H1, and the refrigerating machine oil and the refrigerant containing the antifoaming agent are H1. The forming reduction rate is expressed by ((H1-H2) / H1) × 100 (%), where H2 is the forming height formed when the liquid layer 204 made of the mixture of the above is heated by the heater 202. Is done.

  The four types of antifoaming agents used in this example are an antifoaming agent having a viscosity of 300 cSt based on fluorosilicone, an antifoaming agent having a viscosity of 1000 cSt based on fluorosilicone, and a viscosity based on fluorosilicone. It is a defoaming agent of 10,000 cSt and a silicone-based antifoaming agent as a comparative example. The measurement result of the forming reduction rate of the antifoaming agent having a viscosity of 300 cSt mainly composed of fluorosilicone is shown by white circles in FIG. The measurement result of the foaming reduction rate of the defoamer having a viscosity of 1000 cSt mainly composed of fluorosilicone is indicated by white triangles in FIG. The measurement results of the forming reduction rate of the defoamer having a viscosity of 10,000 cSt mainly composed of fluorosilicone are shown by black circles in FIG. The measurement result of the forming reduction rate of the silicone-based antifoaming agent as a comparative example is shown by diamonds in FIG. The amount of silicone antifoam added as a comparative example is 2000 ppm. The chain line shown in FIG. 5 is a line obtained by linearly interpolating the measurement results of the antifoaming agent having a viscosity of 300 cSt mainly composed of fluorosilicone. The dotted line shown in FIG. 5 is a line obtained by linearly interpolating the measurement result of the antifoaming agent having a viscosity of 1000 cSt mainly composed of fluorosilicone. The solid line shown in FIG. 5 is a line obtained by linearly interpolating the measurement results of the defoamer having a viscosity of 10000 cSt mainly composed of fluorosilicone.

  Further, in FIG. 5, as a reference example, the forming reduction rate measured using a mixture of the fluorine-containing refrigerant R410A and polyvinyl ether is indicated by a white square. To this mixture, 10 ppm of a silicone-based antifoaming agent is added.

  In this example, as shown in FIG. 5, when an antifoaming agent having a viscosity of 10,000 cSt based on fluorosilicone is used, when an antifoaming agent having a limit dissolution amount of 50 ppm or more is added to the refrigerating machine oil, It was confirmed that the forming reduction rate equivalent to the forming reduction rate of the reference example indicated by the white square is achieved. In addition, when an antifoaming agent having a viscosity of 10000 cSt, which is mainly composed of fluorosilicone, is used, it is confirmed that the foaming reduction rate becomes very low when a defoaming agent equivalent to 10 ppm is added to the refrigerating machine oil. It was.

  Further, when a defoaming agent having a viscosity of 300 cSt mainly composed of fluorosilicone and an antifoaming agent having a viscosity of 1000 cSt mainly composed of fluorosilicone are used as the defoaming agent, the forming reduction rate of the reference example indicated by a white square It was confirmed that the amount of antifoaming agent added must be at least 1000 ppm in order to achieve a forming reduction rate equivalent to.

  Therefore, in this embodiment, when R32 is used as the refrigerant circulating in the refrigerant circuit of the refrigeration apparatus, it is generated when the compressor is started by adding an amount of antifoaming agent exceeding the limit dissolution amount to the refrigeration oil. It was confirmed that forming can be sufficiently suppressed.

  The refrigerating apparatus according to the present invention can suppress a decrease in refrigerating machine oil stored in the compressor.

110 Refrigerant circuit 112 Compressor 120 Air conditioner (refrigeration unit)

JP 59-128986 A JP 2010-210208 A

Claims (4)

A compressor (112) for compressing the refrigerant;
A refrigerant circuit (110) in which a fluid containing the refrigerant and refrigeration oil is enclosed, and the refrigerant is circulated by the compressor to perform a refrigeration cycle;
With
The fluid is added with an antifoaming agent in an amount exceeding the limit dissolution amount,
The limit dissolution amount is the maximum amount of the antifoaming agent that can be dissolved in the refrigerating machine oil contained in the fluid at normal temperature and atmospheric pressure.
Refrigeration equipment (120). The fluid is added with the antifoaming agent that dissolves in the refrigerant.
The refrigeration apparatus according to claim 1. The antifoaming agent is mainly composed of fluorosilicone,
The refrigeration apparatus according to claim 2. The refrigerant contains fluorine;
The refrigeration apparatus according to any one of claims 1 to 3.

Images