KR102103225B1 - Refrigeration unit - Google Patents

Abstract

The refrigeration apparatus is equipped with a refrigerant circuit that circulates the refrigerant by connecting a compressor, a condenser, an expansion mechanism, and an evaporator through a refrigerant pipe. The refrigerant contains at least 10% by weight of the HFO-based refrigerant, and at least 50% by weight of the HFC-based refrigerant, and the refrigerating agent oil that lubricates the sliding portion of the compressor has an additive amount of 0.1 to 1.0% by weight. (酸 捕捉 劑) is blended.

Description

Refrigeration unit

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

Background Art Conventionally, a refrigerating machine oil used in a refrigerating apparatus such as an air conditioner contains a substance for suppressing the deterioration of the refrigerating machine oil and corrosion of the expansion valve by acid such as hydrofluoric acid generated by decomposition of the refrigerant. For example, Patent Document 1 below discloses a lubricating oil composition for a refrigerator, in which an amount of an acid-adhesive agent (0.005 to 10.0% by weight) added to the refrigerator oil is blended.

In addition, fluorine-based refrigerants such as R32 as a single refrigerant and R410A and R407C as a mixed refrigerant are conventionally used as a refrigerant circulating the refrigeration cycle of a refrigeration apparatus such as an air conditioner. However, since these fluorine-based refrigerants do not contain chlorine, the effect of destroying the ozone layer is small, but there is a problem that the effect on global warming is large due to the greenhouse effect. Thus, in recent years, HFO-1234yf refrigerants, HFO-1234ze (E) refrigerants, and the like have been noted as propylene-based fluorohydrocarbon refrigerants having a small global warming coefficient and a small effect on global warming.

Patent Document 1: Japanese Patent Application Publication No. 2011-202031

Propylene-based fluorinated hydrocarbon refrigerants have lower stability than other fluorine-based refrigerants such as R32 and R410A, and are easily decomposed by being placed in a high-temperature environment or mixed with air and water, and also generate a large amount of acid such as hydrofluoric acid due to decomposition. . Acid generated by the decomposition of the refrigerant deteriorates the refrigerating machine oil used in the refrigeration apparatus and corrodes components such as expansion valves, but the sliding wear and tear of the compressor constituting the refrigerating machine oil cargo and the air conditioner (磨耗)粉) Combines to become a contaminant (hereinafter referred to as sludge), and there is a concern that refrigerant circuit components such as expansion valves may be blocked. Further, based on the lubricating oil composition for a freezer disclosed in Patent Document 1, when 10% by weight of an acid scavenger is added, the amount of fluorine can be suppressed, but the occurrence of abnormal sludge can be suppressed. none.

In addition, the propylene-based fluorohydrocarbon refrigerant has better compatibility with the refrigerating machine oil than other fluorine-based refrigerants, and the refrigerant is melted in the sliding portion of the compressor to supply the refrigerating machine oil having a low viscosity, thereby providing the sliding portion of the compressor. Abnormal heat generation is caused by metal contact, and acid generation by decomposition of the refrigerant is promoted.

The present invention has been made to solve the problems as described above, and it is an object of the present invention to provide a highly reliable refrigeration device by suppressing deterioration of refrigeration oil, corrosion of a expansion valve, and occurrence of sludge abnormality.

A refrigerating device according to the present invention is a refrigerating device having a refrigerant circuit that circulates refrigerant by connecting a compressor, a condenser, an expansion mechanism, and an evaporator to a refrigerant pipe, wherein the refrigerant comprises at least 10% by weight of HFO-based refrigerant, The refrigerating machine oil containing at least 50% by weight of HFC-based refrigerant and lubricating the sliding portion of the compressor contains an additive amount of 0.1 to 1.0% by weight.

The refrigerating device of the present invention uses a propylene-based hydrocarbon or a mixture containing propylene-based fluorohydrocarbons as a refrigerant, and is also effective in capturing an acid such as hydrofluoric acid by refrigerant decomposition in a refrigerant oil enclosed in a compression element. Since it is a composition in which a scattering agent is blended, it is possible to suppress deterioration of the refrigerator oil, corrosion of the expansion valve, and abnormal occurrence of sludge.

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

Embodiment.

Below, the structure and operation | movement of the refrigerating apparatus which concerns on this invention are demonstrated based on embodiment shown. 1 is a schematic diagram schematically showing a refrigerant circuit of a refrigerating device according to an embodiment of the present invention. As shown in Fig. 1, the refrigeration device 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 ( 6) is sequentially connected to the refrigerant pipe, and is provided with a refrigerant circuit circulating the refrigerant, and is used for indoor air conditioning by performing a vapor compression type refrigeration cycle operation.

The compressor 2 compresses the sucked refrigerant and discharges it in a high temperature and high pressure state, the refrigerant discharge side is connected to the four-way switching valve 3, and the refrigerant suction side is connected to the accumulator 9. The compressor 2 is, as an example, a configuration that enables variable operation capacity (frequency), and uses, for example, a positive displacement compressor driven by a motor (not shown) controlled by an inverter. .

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 arrow in FIG. 1 during cooling operation. The refrigerant flow path is switched to connect the refrigerant suction side of (2) and the gas side of the indoor heat exchanger (6). On the other hand, during 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 shown by the broken arrow in FIG. 1. , The refrigerant flow path is switched 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 during cooling operation, and performs heat exchange between the refrigerant discharged from the compressor (2) and air. In addition, the outdoor heat exchanger 4 functions as an evaporator during the heating operation, so as to exchange heat between the refrigerant flowing out from the expansion mechanism 5 and air. The outdoor heat exchanger (4) sucks outdoor air by the outdoor blower (7), and discharges the heat exchanged between the refrigerant to the outdoors. 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 expands by reducing the refrigerant flowing in the refrigerant circuit under reduced pressure, and as an example, is composed of an electromagnetic expansion valve in which the opening degree is variably controlled. 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 from the expansion mechanism (5) and air. In addition, the indoor heat exchanger 6 functions as a condenser during heating operation, so as to exchange heat between the refrigerant discharged from the compressor 2 and air. The indoor heat exchanger (6) sucks indoor air by the indoor blower (8), and supplies the air heat exchanged with the refrigerant to the indoor. 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 refrigerating device 1 during 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 high-temperature, high-pressure gas refrigerant condenses and becomes a high-pressure liquid refrigerant. The liquid refrigerant passing through the outdoor heat exchanger (4) passes through the expansion valve of the expansion mechanism (5) to become 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, 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 latent heat of evaporation of the refrigerant generated in the indoor heat exchanger (6). On the other hand, during 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, the latent heat of condensation of the refrigerant generated in the outdoor heat exchanger (4) causes the room to overheat.

In the present embodiment, as the refrigerant circulating through the refrigerant circuit of the refrigerating device 1, an HFO-based refrigerant that is a propylene-based fluorohydrocarbon refrigerant is used. Specifically, the HFO-based refrigerant is a HFO single substance or a mixed refrigerant containing 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). Moreover, the global warming coefficient as a mixed refrigerant is preferably 1000 or less, and more preferably 500 or less.

The HFO-based refrigerant has a smaller influence on global warming than fluorine-based refrigerants such as R32, which is a single refrigerant, and R410A and R407C, which are mixed refrigerants. However, since the stability is low, hydrogen fluoride (hydrofluoric acid) by decomposition, formic acid, acetic acid, etc. The amount of acid generated is large. The acid generated by the decomposition of the refrigerant is dissolved in water contained in the refrigerant and the refrigerant oil, circulates the refrigerant circuit, degrades the refrigerant oil, and when acid is attached to the expansion valve of the expansion mechanism 5, metal parts of the expansion valve This corrosion causes abnormality of the expansion mechanism 5. In addition, there is a fear that the refrigerant oil deteriorated by the acid and the sliding wear powder of the compressor 2 are combined and become sludge, clogging refrigerant circuit components such as an expansion valve.

Next, an example of an operation mode of the refrigerating device 1, in which decomposition of the HFO refrigerant is likely to occur, is given. When the temperature of the high-pressure gas refrigerant discharged from the compressor 2 is, for example, an operation exceeding 120 ° C., the temperature of the sliding portion inside the compressor 2 may be locally high, resulting in HFO refrigerant. May decompose. In addition, when a large amount of liquid refrigerant is returned to the compressor 2 when the refrigerating device 1 is started, the liquid refrigerant is dissolved in the refrigerating machine oil of the compressor 2, and the low-viscosity refrigerator oil is supplied to the sliding portion of the compressor 2 There is driving that is done in the state of being. In this case, the sliding portion of the compressor 2 causes metal contact, and there is a fear that the HFO refrigerant is thermally decomposed by abnormal heat generation of the sliding portion.

Thus, the freezer oil used in the refrigerating device 1 of the present embodiment contains 0.1 to 1.0% by weight of an acid scavenger. Refrigerator oil is a lubricant used to prevent wear and sticking at the sliding portion of the compressor 2. The sliding portion of the compressor 2 is, for example, when the compressor 2 is a rotary compressor, a sliding surface between a vane and a roller, and a sliding surface between a crankshaft and a shaft. The acid scavenger is an additive used to capture acids such as hydrofluoric acid generated by decomposition of the HFO-based refrigerant.

Next, the composition of the refrigerating machine oil used in the present embodiment will be described. Refrigerator oil is mainly composed of a base oil, a scattering agent, an extreme pressure agent, and an antioxidant.

As the base oil, mineral oil or synthetic oil is used. Although the base oil has good compatibility with the HFO-based refrigerant used in the refrigeration apparatus 1, a refrigerating machine oil having a viscosity that enables fluid lubrication at the sliding portion of the compressor 2 is appropriately selected. Mineral oils are, for example, naphthenic mineral oils and paraffinic mineral oils. Synthetic oils include, for example, polyvinyl ether, polyol esters, polyalkylene glycols, and alkylbenzenes. In this embodiment, it is preferable to use synthetic oils such as polyvinyl ether and polyol ester as the base oil. Moreover, as a base oil, you may use the mixture which combined 2 or more types of said mineral oil or synthetic oil.

The acid scavenger is an additive used to suppress deterioration of the refrigerating machine oil by the acid by reacting with an acid such as hydrofluoric acid generated by decomposition of the HFO-based refrigerant. The scattering agent is contained in the freezer oil from 0.1% by weight to 1.0% by weight. Acid scavengers are, for example, epoxy compounds, carbodiimide compounds, and terpene-based compounds.

The extreme pressure agent is an additive used to prevent abrasion and sticking in sliding parts such as the compressor 2. The refrigerating machine oil prevents contact between the sliding members by forming an oil film between the surfaces of the members sliding from each other in the sliding portion. However, when the base oil viscosity is low, the refrigerant oil is melted in large quantities to lower viscosity, or the pressure applied to the slide member is high, the refrigerating machine oil is liable to make metal contact between the slide members. Even in the case of the above, the extreme pressure agent suppresses the occurrence of abrasion and sticking by reacting with the surface of the member sliding from each other in the sliding portion and forming a coating film. The extreme pressure agent is, for example, phosphate ester, phosphorous acid ester, thiophosphate, sulfide ester, and the like, and specific examples thereof include tricresyl phosphate (TCP), triphenyl phosphate (TPP), and triphenylphosphorothioate (TPPT). Can be mentioned.

Antioxidants are additives used to prevent oxidation of the refrigerating machine oil. Specific examples of antioxidants include dithiozinc phosphate, organic sulfur compounds, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,2 ' Phenolic antioxidants such as methylenebis (4-methyl-6-tert-butylphenol), amine antioxidants such as phenyl-α-naphthylamine, N, N'-di-phenyl-p-phenylenediamine, And N N'-disalicylidene-1 2-aminopropane.

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

The test conditions for the product practical test were the temperature of the refrigerant gas discharged from the compressor 2, 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. . As the base oil of the refrigerating machine oil, polyvinyl ether oil was used. The amount of the scattering agent added to the refrigerating machine 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. The condition of the expansion valve of the expansion mechanism 5 of 1) was confirmed. Specifically, the expansion valve after the test was elementally analyzed with an X-ray apparatus to confirm the amount of fluorine as a refrigerant decomposition product and the amount of sludge attached to the expansion valve. Table 1 below shows the test results of the product practical test.

[Table 1]

As a criterion for determining whether the refrigerating machine oil passed or failed, the evaluation result of the R410A refrigerant was referred to, and the case where the fluorine detection amount was 5% by weight or less and the sludge generation amount was 1% by weight or less was considered to be rejected.

In Table 1, in the cases of "I" and "II", in which the amount of the scattering agent added was 0.005 to 0.05% by weight, the fluorine detection amount was higher than 5% by weight, and corrosion of the expansion valve was confirmed, so it was judged as rejected. In addition, in the cases of "V" and "VI" in which the amount of the scattering agent added was 6 to 10% by weight, the amount of sludge generated was 1% by weight or more, and mass generation of sludge was confirmed, so it was judged as unsuccessful. On the other hand, in the cases of "III" and "IV" in which the amount of the acid-adhesive agent added was 0.1 to 1.0% by weight, the amount of fluorine detected and the amount of sludge generated were determined to pass because it was confirmed that there was no problem.

From Table 1, in the refrigeration apparatus using HFO-based refrigerant, corrosion and sludge abnormality of the expansion valve were suppressed when the amount of the acid-removing agent added to the refrigerating machine oil was 0.1 to 1.0% by weight.

In addition, when the amount of the acid-adhesive agent added was 0.2 to 1.0% by weight, it was confirmed that the fluorine detection amount was significantly lowered, and the corrosion resistance effect of the expansion valve was improved.

Therefore, in the refrigeration device 1 of the present embodiment, acids such as hydrofluoric acid generated by decomposition of the HFO-based refrigerant are more preferably 0.2 wt. % To 1.0% by weight. Thereby, deterioration of the refrigerating machine oil due to acid generated by decomposition of the HFO-based refrigerant and corrosion of the expansion valve of the expansion mechanism 5 and abnormal occurrence of sludge are suppressed. Therefore, the reliability of the refrigerating device 1 can be improved.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the configuration of the above-described embodiments. For example, refrigerant circuit elements such as a flow path configuration (pipe connection) of a refrigerant, a compressor 2, a four-way switching valve 3, an outdoor heat exchanger 4, an expansion mechanism 5, and an indoor heat exchanger 6 The contents of the configuration and the like are not limited to those described in the embodiments, and can be appropriately changed within the scope of the technology of the present invention. In short, it is noted that the scope of the present invention (technical scope) also includes various changes, applications, and ranges of use made by a person skilled in the art according to needs.

1: Refrigeration unit
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)

A refrigeration system having a refrigerant circuit that circulates refrigerant by connecting a compressor, a condenser, an expansion mechanism, and an evaporator to a refrigerant pipe,
The refrigerant includes at least 10% by weight of HFO-based refrigerant and at least 50% by weight of HFC-based refrigerant,
The refrigerating device, characterized in that the refrigerating machine oil lubricating the sliding portion of the compressor contains an acid scavenger having an added amount of 0.1% to 1.0% by weight. According to claim 1,
The scavenger is a refrigeration device, characterized in that the addition amount is 0.2% by weight or more. The method according to claim 1 or 2,
A refrigerating device, characterized in that an extreme pressure agent is mixed with the refrigerating machine oil. The method according to claim 1 or 2,
The refrigerating machine is characterized in that an antioxidant is blended in the refrigerating machine oil. The method according to claim 1 or 2,
The refrigerating machine comprises a polyvinyl ether oil. The method according to claim 1 or 2,
Refrigerating apparatus, characterized in that the freezer oil contains polyol esters. The method according to claim 1 or 2,
The refrigerating machine comprises an alkylbenzene oil. The method according to claim 1 or 2,
The HFO-based refrigerant, at least HFO-1234yf, or HFO-1234ze (E), characterized in that the refrigeration apparatus. The method according to claim 1 or 2,
The HFC refrigerant is a refrigeration device, characterized in that R32. The method according to claim 1 or 2,
The refrigerant is a refrigeration device, characterized in that the global warming coefficient is 1000 or less.

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