KR20180099850A - Freezing device - Google Patents

Abstract

The refrigeration apparatus includes a refrigerant circuit for circulating refrigerant by connecting a compressor, a condenser, an expansion mechanism, and an evaporator with a refrigerant pipe. The refrigerant contains at least 10% by weight of the HFO-based refrigerant and at least 50% by weight or more of the HFC-based refrigerant. The refrigerating machine oil for lubricating the sliding portion of the compressor contains an acid pick- (Acid trapping agent) are mixed.

Description

Freezing device

The present invention relates to a refrigerating device in which a refrigerant circulating in a refrigeration cycle is made of a mixture containing propylene-based fluorinated hydrocarbon or propylene-based fluorinated hydrocarbon.

BACKGROUND ART Conventionally, refrigerator oils used in refrigerating apparatuses such as air conditioners contain substances for suppressing deterioration of refrigerating machine oil caused by acids such as hydrofluoric acid or the like and decomposition of expansion valves caused by decomposition of refrigerants. For example, Patent Document 1 below discloses a lubricating oil composition for a refrigerator in which an acid scavenger (acid trapping agent) having an addition amount of 0.005 to 10.0 wt% is added to refrigerator oil.

Conventionally, as a refrigerant circulating in a refrigeration cycle of a refrigerating apparatus such as an air conditioner, a fluoric refrigerant such as R32 as a single refrigerant and R410A and R407C as mixed refrigerants is used. However, since these fluorocarbon-based refrigerants do not contain chlorine, the ozone depletion effect is small, but the effect on the global warming is large due to the greenhouse effect. HFO-1234yf refrigerant, HFO-1234ze (E) refrigerant and the like have recently been attracting attention as a propylene-based fluorinated hydrocarbon refrigerant having a small global warming coefficient and having little influence on global warming.

Patent Document 1: Japanese Patent Application Laid-Open No. 2011-202031

The propylene-based fluorinated hydrocarbon refrigerant has a lower stability than the other fluorinated refrigerants such as R32 and R410A, is easily decomposed by putting it in a high-temperature environment, or by mixing air and water, and also generates a large amount of acid such as hydrofluoric acid . The acid generated by the decomposition of the refrigerant deteriorates the refrigerator oil used in the refrigerating device and may cause corrosion of the components such as the expansion valve and the like, and the sliding wear of the compressor constituting the inside of the air conditioner (Hereinafter referred to as " sludge "), and the refrigerant circuit component such as the expansion valve may be clogged. On the basis of the lubricating oil composition for a refrigerator disclosed in Patent Document 1, when 10% by weight of an acid capturing agent is added, the amount of fluorine generated can be suppressed, but the occurrence of an abnormality of the sludge can be suppressed none.

Further, the propylene-based fluorinated hydrocarbon refrigerant has better compatibility with the refrigerator oil than the other fluorinated refrigerants, and the refrigerant is melted in the active portion of the compressor and the refrigerant oil having a lower viscosity is supplied, The metal comes into contact with an abnormal heat generation to accelerate the generation of acid by decomposition of the refrigerant.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a refrigerating device with high reliability by suppressing deterioration of refrigerator oil, corrosion of an expansion valve and occurrence of abnormality of sludge.

A refrigerating apparatus according to the present invention is a refrigerating apparatus having a refrigerant circuit for circulating a refrigerant through a refrigerant pipe connected to a compressor, a condenser, an expansion mechanism and an evaporator, wherein the refrigerant contains at least 10% by weight of an HFO- The refrigerator oil containing at least 50% by weight of the HFC refrigerant and lubricating the sliding portion of the compressor is blended with an acid scavenger of 0.1 to 1.0% by weight.

INDUSTRIAL APPLICABILITY The refrigeration apparatus of the present invention is a refrigerating apparatus that uses a mixture containing propylene-based fluorocarbon hydrogen or propylene-based fluorocarbon hydrogen as a refrigerant and is effective in capturing an acid such as hydrofluoric acid by decomposition of refrigerant into refrigerant oil sealed in the compression element It is possible to suppress deterioration of the refrigerator oil, corrosion of the expansion valve, and occurrence of abnormality of the sludge.

1 is a schematic diagram schematically showing a refrigerant circuit of a refrigerating device according to an embodiment of the present invention.

Embodiments.

Hereinafter, the configuration and operation of the refrigeration apparatus according to the present invention will be described with reference to the embodiments shown in the drawings. 1 is a schematic diagram schematically showing a refrigerant circuit of a refrigerating apparatus according to an embodiment of the present invention. 1, the refrigeration apparatus 1 of the present embodiment includes a compressor 2, a four-way switching valve 3, an outdoor heat exchanger 4, an expansion mechanism 5, and an indoor heat exchanger (not shown) 6) are sequentially connected to the refrigerant piping to circulate the refrigerant. By performing the vapor compression refrigeration cycle operation, the refrigerant circuit is used for indoor cooling and heating.

The compressor 2 compresses the sucked refrigerant and discharges it in a state of high temperature and high pressure. The refrigerant discharge side is connected to the four-way switching valve 3, and the refrigerant suction side is connected to the accumulator 9. As an example, the compressor 2 is configured so as to be able to vary the operation capacity (frequency), and a positive displacement compressor driven by a motor (not shown) controlled by an inverter is used .

The four-way switching valve 3 has a function of switching the flow path of the refrigerant. The four-way switching valve 3 connects the refrigerant discharge side of the compressor 2 and the gas side of the outdoor heat exchanger 4, as shown by the solid line arrows in Fig. 1, during the cooling operation, The refrigerant passage is switched so that the refrigerant suction side of the indoor heat exchanger 2 and the gas side of the indoor heat exchanger 6 are connected. On the other hand, in the heating operation, the four-way switching valve 3 connects the refrigerant discharge side of the compressor 2 and the gas side of the indoor heat exchanger 6 as indicated by the broken line arrow in Fig. 1 , The refrigerant passage is switched so as to connect the refrigerant suction side of the compressor (2) and the gas side of the outdoor heat exchanger (4).

The outdoor heat exchanger (4) functions as a condenser at the time of cooling operation, and performs heat exchange between the refrigerant discharged from the compressor (2) and the air. The outdoor heat exchanger (4) functions as an evaporator during heating operation, and performs heat exchange between the refrigerant flowing out of the expansion mechanism (5) and the air. The outdoor heat exchanger (4) sucks the outdoor air by the outdoor air blower (7), and discharges the heat-exchanged air with the refrigerant to the outside. In the outdoor heat exchanger (4), the gas side is connected to the four-way switching valve (3) and the liquid side is connected to the expansion mechanism (5).

The expansion mechanism (5) decompresses and expands the refrigerant flowing in the refrigerant circuit, and is constituted by an electronic expansion valve whose opening degree is controlled variably. One of the expansion mechanisms 5 is connected to the outdoor heat exchanger 4 and the other is connected to the indoor heat exchanger 6. [

The indoor heat exchanger (6) functions as an evaporator during cooling operation, and performs heat exchange between the refrigerant flowing out of the expansion mechanism (5) and the air. The indoor heat exchanger (6) functions as a condenser at the time of heating operation, and performs heat exchange between the refrigerant discharged from the compressor (2) and the air. The indoor heat exchanger (6) sucks the indoor air by the indoor air blower (8) and supplies the air exchanged with the refrigerant to the room. In the indoor heat exchanger 6, the gas side is connected to the four-way switching valve 3 and the liquid side is connected to the expansion mechanism 5. [

Next, the operation of the refrigeration apparatus 1 at the time of cooling operation will be described.

The compressor (2) compresses the low-pressure gas refrigerant and discharges the high-temperature and high-pressure gas refrigerant. The refrigerant discharged from the compressor (2) passes through the four-way switching valve (3) and is supplied to the outdoor heat exchanger (4). As the refrigerant passes through the outdoor heat exchanger (4), the gas refrigerant of high temperature and high pressure condenses and becomes a high-pressure liquid refrigerant. The liquid refrigerant that has passed through the outdoor heat exchanger 4 passes through the expansion valve of the expansion mechanism 5 and becomes a low-pressure gas-liquid mixed refrigerant and is supplied to the indoor heat exchanger 6. The refrigerant that has passed through the indoor heat exchanger 6 becomes a low-temperature and low-pressure gas refrigerant from a low-pressure gas-liquid mixed state. The refrigerant that has passed through the indoor heat exchanger (6) is supplied to the compressor (2).

In the cooling operation, the outdoor heat exchanger (4) functions as a condenser, and the indoor heat exchanger (6) functions as an evaporator. That is, the room is cooled by the latent heat of evaporation of the refrigerant generated in the indoor heat exchanger (6). On the other hand, in the heating operation, by switching the four-way switching valve 3, the outdoor heat exchanger 4 functions as an evaporator and the indoor heat exchanger 6 functions as a condenser. That is, due to the latent heat of condensation of the refrigerant generated in the outdoor heat exchanger (4), the room is overheated.

In this embodiment, as the refrigerant circulating through the refrigerant circuit of the refrigerating device 1, an HFO-based refrigerant which is propylene-based fluorocarbon hydrogen refrigerant is used. Specifically, the HFO-based refrigerant is a mixed refrigerant including HFO alone or R32. The mixed refrigerant containing the HFO refrigerant is a mixed refrigerant containing at least 10% by weight of the HFO refrigerant and at least 50% by weight of the R32 refrigerant as the HFC-based refrigerant. The HFO refrigerant is preferably HFO-1234yf and HFO-1234ze (E). The global warming coefficient as a mixed refrigerant is preferably 1000 or less, and more preferably 500 or less.

The HFO-based refrigerant is less influenced by global warming than fluorine-based refrigerants such as R32, which is another single refrigerant, and R410A and R407C, which are mixed refrigerants. However, since hydrogen fluoride (hydrofluoric acid), formic acid and acetic acid The amount of acid generated is large. The acid generated by the decomposition of the refrigerant dissolves in the water contained in the refrigerant and the refrigerating machine oil and circulates through the refrigerant circuit to deteriorate the refrigerator oil. When the acid is adhered to the expansion valve of the expansion mechanism 5, So that it becomes a cause of the expansion mechanism (5). Further, there is a possibility that the refrigerant oil deteriorated by the acid and the sliding abrasion of the compressor 2 are combined and become sludge, thereby clogging the refrigerant circuit component such as the expansion valve.

Next, an example of the operation mode of the refrigerating apparatus 1 in which decomposition of the HFO refrigerant is likely to occur will be described. When the temperature of the high-pressure gas refrigerant discharged from the compressor 2 is, for example, higher than 120 DEG C, the temperature of the sliding portion inside the compressor 2 may become locally high, There is a possibility of pyrolysis. When a large amount of liquid refrigerant returns to the compressor 2 at the start of the refrigerating apparatus 1, the liquid refrigerant dissolves in the refrigerating machine oil of the compressor 2, and the refrigerating machine oil of low viscosity is supplied to the sliding portion of the compressor 2 There is an operation that is performed in a state that the vehicle is in a state that In this case, the sliding portion of the compressor 2 is brought into metal contact, and there is a fear that the HFO refrigerant is thermally decomposed by the abnormal heat of the sliding portion.

Therefore, the refrigerator oil used in the refrigeration apparatus 1 of the present embodiment is blended with 0.1% by weight to 1.0% by weight of the acid trapping agent. The freezer oil is a lubricant used for preventing abrasion and seizure at the sliding portion of the compressor (2). The slide portion of the compressor 2 is, for example, a slide surface between the vane and the roller, and a slide surface between the crankshaft and the bearing when the compressor 2 is a rotary compressor. The acid capturing agent is an additive used for capturing acids such as hydrofluoric acid generated by decomposition of the HFO-based refrigerant.

Next, the composition of the freezer oil used in the present embodiment will be described. The refrigerator oil is mainly composed of a base oil, an acid scavenger, an extreme pressure agent and an antioxidant.

The base oil is mineral oil or synthetic oil. Although the base oil has good compatibility with the HFO-based refrigerant used in the refrigerating apparatus 1, the refrigerating machine oil having a viscosity capable of lubricating the fluid in the sliding portion of the compressor 2 is appropriately selected. The mineral oil is, for example, naphthenic mineral oil or paraffin mineral oil. The synthetic oil includes, for example, polyvinyl ether, polyol ester, polyalkylene glycol, and alkylbenzene. In the present embodiment, it is preferable to use a synthetic oil such as polyvinyl ether or polyol ester as the base oil. As the base oil, a mixture of two or more of the above-mentioned mineral oils or synthetic oils may be used.

The acid capturing agent is an additive which is used for suppressing deterioration of refrigerator oil caused by an acid by reaction with an acid such as hydrofluoric acid generated by decomposition of an HFO-based refrigerant. The acid capturing agent is contained in the refrigerator oil in an amount of 0.1 wt% to 1.0 wt%. The acid capturing agent is, for example, an epoxy compound, a carbodiimide compound, or a tentane compound.

The extreme pressure agent is an additive used for preventing abrasion and seizure at the sliding portion of the compressor (2) or the like. The freezer oil prevents the sliding members from contacting each other by forming an oil film between the sliding surfaces of the sliding members in the sliding portion. However, when the viscosity of the base oil is low, when the refrigerant dissolves in a large amount and becomes low viscosity, or when the pressure applied to the slide member is high, the freezer oil tends to be in metal contact with each other. Even in the case described above, the extreme pressure agent reacts with the surface of the member sliding on the sliding portion and forms a film, thereby suppressing the occurrence of wear and seizure. Examples of the extreme pressure agent include phosphoric acid ester, phosphorous acid ester, thiophosphate and sulfide ester, and specific examples thereof include tricresyl phosphate (TCP), triphenylphosphate (TPP), triphenylphosphorothioate .

The antioxidant is an additive used to prevent oxidation of refrigerator oil. Specific examples of the antioxidant include zinc dithiophosphate, organic sulfur compounds, 2,6-di-tert-butyl-4-methylphenol, 2,6- -Methylenebis (4-methyl-6-tert-butylphenol), amine-based antioxidants such as phenyl-α-naphthylamine and N, N'- N N'-disalicylidene-1-2-aminopropane, and the like.

Next, the influence of refrigerator oil used in the refrigerating device of the present embodiment on the refrigerating device 1 will be described based on Table 1 below. The applicant of the present invention conducted an actual product test and analyzed the influence of the refrigerator oil on the refrigerating device (1).

The test conditions of the product practical test were that the temperature of the refrigerant gas discharged from the compressor 2 was 140 ° C, the operating time of the refrigerating device 1 was 500 hours, and the operating pressure of the refrigerating device 1 was set appropriately . Polyvinyl ether oil was used as the base oil of the freezer. The amount of the acid scavenger added to the refrigerator oil was changed to 0.005% by weight, 0.05% by weight, 0.1% by weight, 1.0% by weight, 6.0% by weight and 10.0% by weight and the freezing device 1 was operated, 1) of the expansion valve 5 of the expansion valve 5 was confirmed. Specifically, the amount of fluorine, which is a decomposition product of refrigerant, and the amount of sludge attached to the expansion valve were checked by elemental analysis of the expansion valve after the test with an X-ray apparatus. Table 1 below shows the test results of the product practical test.

[Table 1]

With reference to the evaluation result of the R410A refrigerant as a criterion for determining whether or not the refrigerating machine oil price was acceptable or not, the fluorine detection amount was 5% by weight or less and the sludge generation amount was 1% by weight or less.

In Table 1, in the case of "I" and "II" in which the addition amount of the acid capturing agent was 0.005 to 0.05 wt%, it was determined that the fluorine detection amount was higher than 5 wt% and the corrosion of the expansion valve was confirmed to be rejected. In the cases of "V" and "VI" in which the addition amount of the acid capturing agent was 6 to 10 wt%, it was determined that the generation of sludge was not less than 1 wt% and the generation of a large amount of sludge was confirmed. On the other hand, in the cases of "III" and "IV" in which the addition amount of the acid capturing agent was 0.1 to 1.0 wt%, the fluorine detection amount and the amount of sludge generation were judged to be acceptable because it was confirmed that there was no problem together.

From Table 1, in the refrigerating machine using the HFO refrigerant, corrosion of the expansion valve and occurrence of sludge abnormality were suppressed when the addition amount of the acid scavenger of the refrigerating machine was 0.1 to 1.0 wt%.

Further, it was confirmed that when the addition amount of the acid scavenger is from 0.2 to 1.0% by weight, the fluorine detection amount is remarkably lowered and the corrosion resistance effect of the expansion valve is improved.

Therefore, in the refrigerating machine 1 of the present embodiment, the acid such as hydrofluoric acid generated by the decomposition of the HFO refrigerant is preferably added to the refrigerator oil by an acid scavenger containing 0.1 wt% to 1.0 wt%, more preferably 0.2 wt% % To 1.0% by weight of an acid scavenger. As a result, deterioration of the refrigerating machine oil caused by the acid generated by decomposition of the HFO refrigerant and corrosion of the expansion valve of the expansion mechanism 5 and occurrence of abnormality of the sludge are suppressed. Therefore, the reliability of the refrigerating apparatus 1 can be improved.

Although the present invention has been described based on the embodiments thereof, the present invention is not limited to the configurations of the above-described embodiments. For example, the refrigerant circuit elements (refrigerant circuit elements) of the refrigerant flow path configuration (piping connection), the compressor 2, the four-way switching valve 3, the outdoor heat exchanger 4, the expansion mechanism 5, And the like are not limited to the contents described in the embodiments, but can be appropriately changed within the scope of the technology of the present invention. In short, it is added for the sake of convenience that the scope of the various changes, applications, and uses that the person skilled in the art makes in response to the needs is included in the gist of the present invention (technical scope).

1: Freezer
2: Compressor
3: 4-way switching valve
4: outdoor heat exchanger
5: Expansion mechanism
6: Indoor heat exchanger
7: Outdoor blower
8: Indoor blower
9: Accumulator

Claims (10)

1. A refrigerating device comprising a refrigerant circuit for circulating a refrigerant by connecting a compressor, a condenser, an expansion device, and an evaporator with a refrigerant pipe,
Wherein the refrigerant comprises at least 10% by weight of an HFO-based refrigerant and at least 50% by weight or more of an HFC-based refrigerant,
Characterized in that the refrigerator oil for lubricating the slide portion of the compressor is blended with an acid scavenger which is added in an amount of 0.1 wt% to 1.0 wt%. The method according to claim 1,
Wherein the acid capturing agent is added in an amount of 0.2 wt% or more. 3. The method according to claim 1 or 2,
Wherein the refrigerating machine oil is mixed with an extreme pressure agent. 4. The method according to any one of claims 1 to 3,
Wherein an antioxidant is mixed in the freezer oil. 5. The method according to any one of claims 1 to 4,
Wherein the freezer oil contains polyvinyl ether oil. 5. The method according to any one of claims 1 to 4,
Wherein the freezer oil contains a polyol ester. 5. The method according to any one of claims 1 to 4,
Wherein the refrigerating machine oil contains alkylbenzene oil. 8. The method according to any one of claims 1 to 7,
Wherein the HFO-based refrigerant is at least HFO-1234yf or HFO-1234ze (E). 9. The method according to any one of claims 1 to 8,
And the HFC refrigerant is R32. 10. The method according to any one of claims 1 to 9,
Wherein the refrigerant has a global warming coefficient of 1000 or less.

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