JP2009264709A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a copper plating phenomenon and to improve reliability in a refrigerating device having a refrigerant circuit filled with a carbon dioxide refrigerant. <P>SOLUTION: An air conditioner 1 includes the refrigerant circuit 2, the carbon dioxide refrigerant, lubricating oil and an acid neutralizer. In the refrigerant circuit 2, a compressor 11, an indoor heat exchanger 31, an outdoor heat exchanger 13, a first expansion valve 15 and a second expansion valve 17 are interconnected. The carbon dioxide refrigerant is filled in the refrigerant circuit 2. The lubricating oil is filled in the compressor 11, and the acid neutralizer is mixed in the lubricating oil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus that can suppress a copper plating phenomenon.

  Usually, in the refrigeration apparatus, the reactions shown in the following chemical reaction formulas (1) to (4) occur due to moisture mixed in the refrigerant in the refrigerant circuit, and copper ions are generated in the refrigerant. When copper ions are generated in the refrigerant, a reaction shown in the following chemical reaction formula (5) occurs, and thus a phenomenon that the components of the refrigeration apparatus are plated with copper (hereinafter referred to as a copper plating phenomenon) occurs. When this copper plating phenomenon occurs on the surface of the sliding part of the compressor, noise is generated during operation of the compressor, which causes a problem of adversely affecting the reliability of the compressor.

Moreover, the metallic materials of the components in the refrigeration apparatus are corroded by acidic substances such as hydrogen ions generated by the reactions shown in the following chemical reaction formulas (1) to (3). Furthermore, if a chlorine-containing component remains as a process auxiliary material in the refrigeration apparatus, a reaction represented by the following chemical reaction formula (6) occurs. For this reason, hydrogen chloride which is a strong acid is generated, and the corrosion of the metal material and the copper plating phenomenon are further accelerated.

Therefore, in a refrigeration apparatus using a hydrofluorocarbon refrigerant (hereinafter referred to as an HFC refrigerant), a method of adding a specific carbodiimide compound to the refrigerator oil in order to suppress the copper plating phenomenon and the generation of acidic substances (Patent Document 1). And a method of adding a cyclic polyether oil by applying a hydrocarbon oil as a refrigerating machine oil (see Patent Document 2).
JP-A-8-120288 JP 2001-152172 A

  By the way, in recent years, with the development of industrial technology, a carbon dioxide refrigerant may be applied as a refrigerant in the refrigerant circuit. Since carbon dioxide refrigerant has less saturated water content than HFC refrigerants, carbon dioxide refrigerant is mixed in the refrigeration equipment when carbon dioxide refrigerant is used as the refrigerant in the refrigeration equipment, compared to when HFC refrigerant is applied. Moisture that appears is likely to appear in a liquid state. For this reason, acidic substances are more likely to be generated, and the copper plating phenomenon is more likely to occur. Therefore, there arises a problem that the reliability of the compressor is further adversely affected.

  For such problems, it is conceivable to use the additives disclosed in Patent Document 1 and Patent Document 2, but when carbon dioxide is used as the refrigerant, there is a possibility that the copper plating phenomenon cannot be suppressed.

  An object of the present invention is to suppress a copper plating phenomenon and improve its reliability in a refrigeration apparatus including a refrigerant circuit filled with a carbon dioxide refrigerant.

  The refrigeration apparatus according to the first invention includes a refrigerant circuit, a carbon dioxide refrigerant, lubricating oil, and an acid neutralizer. A compressor, a use side heat exchanger, a heat source side heat exchanger, and an expansion mechanism are connected to the refrigerant circuit. The carbon dioxide refrigerant is filled in the refrigerant circuit. Lubricating oil is filled in the compressor. The acid neutralizer is mixed in the lubricating oil.

  In the refrigeration apparatus according to the first aspect of the invention, an acid neutralizer is mixed in the lubricating oil filled in the compressor. For this reason, the acidic substance produced | generated by operating a freezing apparatus is neutralized. Therefore, the corrosion of the metal material due to the acidic substance can be suppressed, and the occurrence of the copper plating phenomenon can be suppressed.

  Thereby, in a refrigeration apparatus including a refrigerant circuit filled with carbon dioxide refrigerant, the copper plating phenomenon can be suppressed and the reliability thereof can be improved.

  The refrigeration apparatus according to the second invention is the refrigeration apparatus according to the first invention, wherein the acid neutralizing agent is a basic detergent. The cleaning agent can prevent deterioration products generated during operation of the compressor from becoming insoluble sludge. For this reason, in this refrigeration apparatus, generation | occurrence | production of sludge can be suppressed.

  The refrigeration apparatus according to the third invention is the refrigeration apparatus according to the second invention, wherein the acid neutralizing agent is at least one basic detergent selected from the group consisting of sulfonate, phenate, salicylate, and naphthenate. As a result of intensive studies by the inventors, it has been found that at least one detergent selected from the group consisting of sulfonates, phenates, salicylates and naphthenates is suitable as an acid neutralizer. Therefore, in this refrigeration apparatus, a high effect can be obtained by using at least one basic detergent selected from the group consisting of sulfonate, phenate, salicylate and naphthenate as an acid neutralizer.

  In the refrigeration apparatus according to the first invention, in the refrigeration apparatus including the refrigerant circuit filled with the carbon dioxide refrigerant, the copper plating phenomenon can be suppressed and the reliability thereof can be improved.

  In the refrigeration apparatus according to the second invention, generation of sludge can be suppressed.

  In the refrigeration apparatus according to the third invention, a high effect can be obtained by using at least one basic detergent selected from the group consisting of sulfonate, phenate, salicylate and naphthenate as the acid neutralizer.

<Configuration of air conditioner>
FIG. 1 shows a schematic refrigerant circuit 2 of an air conditioner 1 according to an embodiment of the present invention.

  This air conditioner 1 is an air conditioner capable of cooling operation and heating operation, and mainly includes a refrigerant circuit 2, an outdoor fan 26 and an indoor fan 32, which will be described later. The refrigerant circuit 2 is filled with carbon dioxide refrigerant.

  The refrigerant circuit 2 mainly includes a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, an internal heat exchanger 14, a first expansion valve 15, a liquid receiver 16, a second expansion valve 17, and indoor heat. An exchanger 31 is provided, and each device is connected via a refrigerant pipe as shown in FIG.

  In the present embodiment, the air conditioner 1 is a separation-type air conditioner, and includes an indoor unit 30 mainly including an indoor heat exchanger 31 and an indoor fan 32, a compressor 11, and a four-way switching valve 12. The outdoor unit 10 mainly including the outdoor heat exchanger 13, the internal heat exchanger 14, the first expansion valve 15, the liquid receiver 16 and the second expansion valve 17, the refrigerant liquid pipe 33 of the indoor unit 30, and the outdoor unit 10. The first communication pipe 41 that connects the refrigerant liquid pipe 20 and the refrigerant gas pipe 34 of the indoor unit 30 and the second communication pipe 42 that connects the refrigerant gas pipe 21 of the outdoor unit 10. The refrigerant liquid pipe 20 and the first connection pipe 41 of the outdoor unit 10 are connected to the outdoor unit 10 via the first closing valve 18 of the outdoor unit 10, and the refrigerant gas pipe 21 and the second connection pipe 42 of the outdoor unit 10 are connected to the outdoor unit 10. The second closing valves 19 are connected to each other. The first closing valve 18 and the second closing valve 19 are opened after the pipes 20, 21, 41, 42 are connected.

(1) Indoor unit The indoor unit 30 mainly includes an indoor heat exchanger 31 and an indoor fan 32.

  The indoor heat exchanger 31 is a heat exchanger for exchanging heat between indoor air, which is air in the air-conditioned room, and the refrigerant.

  The indoor fan 32 is a fan for taking in air in the air-conditioned room into the indoor unit 30 and sending out conditioned air, which is air after heat exchange with the refrigerant via the indoor heat exchanger 31, into the air-conditioned room again.

  By adopting such a configuration, the indoor unit 30 exchanges heat between the indoor air taken in by the indoor fan 32 and the liquid refrigerant flowing through the indoor heat exchanger 31 during the cooling operation, thereby conditioned air ( It is possible to generate conditioned air (warm air) by exchanging heat between the indoor air taken in by the indoor fan 32 and the supercritical refrigerant flowing through the indoor heat exchanger 31 during heating operation. It has become.

(2) Outdoor unit The outdoor unit 10 mainly includes a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, an internal heat exchanger 14, a first expansion valve 15, a liquid receiver 16, and a second expansion valve. 17 and an outdoor fan 26 and the like.

  The compressor 11 is a device for sucking low-pressure gas refrigerant flowing through the suction pipe, compressing it into a supercritical state, and then discharging it to the discharge pipe. The compressor 11 includes at least one lubricating oil selected from the group consisting of polyalkylene glycol oil, polyvinyl ether oil, mineral oil (such as naphthene and paraffin), alkylbenzene oil, polyol ester oil, and cyclic ether oil. Being injected. In addition, a predetermined amount of a basic detergent dispersant is added to the lubricating oil as an acid neutralizer. Examples of the basic detergent dispersant used as the acid neutralizer include sulfonate (see Formula 1 below), phenate (see Formula 2 below), salicylate (see Formula 3 below), and naphthenate. Can be mentioned.

  The four-way switching valve 12 is a valve for switching the flow direction of the refrigerant corresponding to each operation, and connects the discharge side of the compressor 11 and the gas side of the outdoor heat exchanger 13 during the cooling operation and is connected to the compressor. 11 and the gas side of the indoor heat exchanger 31 can be connected via the internal heat exchanger 14. Further, during the heating operation, the four-way switching valve 12 connects the discharge side of the compressor 11 and the second closing valve 19 via the internal heat exchanger 14, and at the same time the suction side of the compressor 11 and the outdoor heat exchanger 13. It is possible to connect to the gas side.

  The outdoor heat exchanger 13 can cool the high-pressure supercritical refrigerant discharged from the compressor 11 during the cooling operation using air outside the air conditioning room as a heat source, and during the heating operation, the indoor heat exchanger 31 can be cooled. It is possible to evaporate the liquid refrigerant returning from.

  The internal heat exchanger 14 connects a refrigerant pipe (hereinafter referred to as a first refrigerant pipe) that connects the liquid side of the outdoor heat exchanger 13 and the first expansion valve 15, a four-way switching valve 12, and the compressor 11. It is the heat exchanger comprised by arrange | positioning refrigerant | coolant piping (henceforth a 2nd refrigerant | coolant piping) to perform in the vicinity. In the internal heat exchanger 14, heat exchange is performed between the high-temperature and high-pressure supercritical refrigerant flowing through the first refrigerant pipe and the low-temperature and low-pressure gas refrigerant flowing through the second refrigerant pipe during the cooling operation.

  The first expansion valve 15 is used to depressurize the supercritical refrigerant (at the time of cooling operation) that flows out from the liquid side of the outdoor heat exchanger 13 or the liquid refrigerant that flows through the receiver 16 (at the time of heating operation). Is.

  The liquid receiver 16 is for storing a surplus refrigerant according to the operation mode and the air conditioning load.

  The second expansion valve 17 depressurizes the liquid refrigerant (during cooling operation) flowing in through the liquid receiver 16 or the supercritical refrigerant (during heating operation) flowing out from the liquid side of the indoor heat exchanger 31. Is for.

  The outdoor fan 26 is a fan for taking outdoor air into the outdoor unit 10 and discharging the air after exchanging heat with the refrigerant via the outdoor heat exchanger 13.

<Operation of air conditioner>
The operation of the air conditioner 1 will be described with reference to FIG. As described above, the air conditioner 1 can perform a cooling operation and a heating operation.

(1) Cooling operation During the cooling operation, the four-way switching valve 12 is in the state indicated by the solid line in FIG. 1, that is, the discharge side of the compressor 11 is connected to the gas side of the outdoor heat exchanger 13, and the compressor 11 Is connected to the second closing valve 19 via the internal heat exchanger 14. At this time, as described above, the first closing valve 18 and the second closing valve 19 are opened.

  When the compressor 11 is started in the state of the refrigerant circuit 2, after the gas refrigerant is sucked into the compressor 11 and compressed to become a supercritical state, the outdoor heat is passed through the four-way switching valve 12. It is sent to the exchanger 13 and cooled in the outdoor heat exchanger 13.

  Then, the cooled supercritical refrigerant is sent to the first expansion valve 15 via the internal heat exchanger 14. At this time, the supercritical refrigerant is cooled by a low-temperature gas refrigerant flowing through the second refrigerant pipe of the internal heat exchanger 14. The supercritical refrigerant sent to the first expansion valve 15 is depressurized and saturated, and then sent to the second expansion valve 17 via the liquid receiver 16. The saturated refrigerant sent to the second expansion valve 17 is reduced in pressure to become liquid refrigerant, and then supplied to the indoor heat exchanger 31 via the first closing valve 18 to cool indoor air and evaporate. It becomes a gas refrigerant.

  Then, the gas refrigerant is sucked into the compressor 11 again via the second closing valve 19, the internal heat exchanger 14 and the four-way switching valve 12. At this time, the gas refrigerant is heated by the high-temperature supercritical refrigerant flowing through the first refrigerant pipe of the internal heat exchanger 14. In this way, the cooling operation is performed.

(2) Heating operation During the heating operation, the four-way switching valve 12 is in the state indicated by the broken line in FIG. 1, that is, the discharge side of the compressor 11 is connected to the second closing valve 19 and the suction side of the compressor 11 is It is in a state of being connected to the gas side of the outdoor heat exchanger 13 via the internal heat exchanger 14. At this time, as described above, the first closing valve 18 and the second closing valve 19 are opened.

  When the compressor 11 is started in the state of the refrigerant circuit 2, the gas refrigerant is sucked into the compressor 11 and compressed into a supercritical state, and then the four-way switching valve 12 and the second closing valve 19 are opened. It is supplied to the indoor heat exchanger 31 via.

  And the refrigerant | coolant of the supercritical state heats indoor air in the indoor heat exchanger 31, and is cooled. The cooled supercritical refrigerant is sent to the second expansion valve 17 through the first closing valve 18. The supercritical refrigerant sent to the second expansion valve 17 is depressurized and saturated, and then sent to the first expansion valve 15 via the liquid receiver 16. The saturated refrigerant sent to the first expansion valve 15 is reduced in pressure to become a liquid refrigerant, and then sent to the outdoor heat exchanger 13 via the internal heat exchanger 14, and is evaporated in the outdoor heat exchanger 13. It becomes a gas refrigerant. At this time, the gas refrigerant is heated by the high-temperature supercritical refrigerant flowing through the second refrigerant pipe of the internal heat exchanger 14. Then, this gas refrigerant is sucked into the compressor 11 again via the four-way switching valve 12. In this way, the heating operation is performed.

<Suppression of copper plating phenomenon>
Hereinafter, a copper plating test and the result are shown as an Example and a comparative example.

  30 g of polyalkylene glycol oil containing 0.5% acid scavenger (epoxy compound) and 5% acid neutralizer (high basic calcium sulfonate) in autoclave, 31 g carbon dioxide refrigerant, 100 mg copper oxide After adding the iron pieces, the autoclave was sealed and left at 120 degrees Celsius for 10 days.

  And after that, when it was confirmed whether the copper plating was formed in the iron piece, the copper plating was not formed.

  Moreover, as a result of measuring the elution amount of iron replaced with copper, elution of iron could not be confirmed.

(Comparative example)
A copper plating test was conducted under the same conditions as in Example 1 except that no acid neutralizer (highly basic calcium sulfonate) was added. As a result, copper plating was formed on the iron piece. As a result of measuring the amount of iron elution, iron elution was confirmed.

  In addition, in the present Example, it turned out that a copper plating phenomenon can be suppressed by restraining the density | concentration of hydrogen chloride to 100 ppm or less.

<Features>
(1)
Since the carbon dioxide refrigerant has a lower saturated water content than the HFC refrigerant, the refrigeration is more effective when the carbon dioxide refrigerant is applied as the refrigerant of the refrigeration apparatus such as an air conditioner than when the HFC refrigerant is applied. Moisture mixed in the apparatus tends to appear in a liquid state. For this reason, acidic substances are more likely to be generated, and the copper plating phenomenon is more likely to occur. When this copper plating phenomenon occurs on the surface of the sliding part of the compressor, noise is generated during operation of the compressor. Therefore, there arises a problem that the reliability of the compressor is adversely affected. Moreover, the problem that the metal material of the component in a freezing apparatus corrodes by the generated acidic substance will also arise.

  To solve such problems, the addition disclosed in Japanese Patent Laid-Open Nos. 8-120288 and 2001-152172 is a method for suppressing the copper plating phenomenon and the generation of acid in a refrigeration apparatus using an HFC-based refrigerant. It is conceivable to use a specific carbodiimide compound or a cyclic polyether oil which is an agent, but when carbon dioxide is used as a refrigerant, there is a possibility that the copper plating phenomenon cannot be suppressed.

  So, in the said embodiment, the compressor 11 connected to the refrigerant circuit 2 is filled with the lubricating oil in which the acid neutralizer is mixed. For this reason, the acidic substance produced | generated when the air conditioning apparatus 1 works is neutralized. Therefore, the corrosion of the metal material due to the acidic substance can be suppressed, and the occurrence of the copper plating phenomenon can be suppressed.

  Thereby, in the air conditioning apparatus 1 including the refrigerant circuit 2 filled with carbon dioxide refrigerant, the copper plating phenomenon can be suppressed and the reliability thereof can be improved.

(2)
In the above embodiment, a basic detergent dispersant is added to the lubricating oil as an acid neutralizer. The cleaning agent can prevent degradation products generated during operation of the compressor from becoming insoluble sludge. For this reason, generation | occurrence | production of sludge can be suppressed.

  The refrigerating apparatus according to the present invention is useful for application to a refrigerating apparatus in which carbon dioxide is used as a refrigerant in order to suppress the copper plating phenomenon and improve its reliability.

The refrigerant circuit figure of the air conditioning apparatus which concerns on embodiment of this invention.

Explanation of symbols

1 Air conditioning equipment (refrigeration equipment)
2 Refrigerant circuit 11 Compressor 13 Outdoor heat exchanger (heat source side heat exchanger)
15 First expansion valve (expansion mechanism)
17 Second expansion valve (expansion mechanism)
31 Indoor heat exchanger (use side heat exchanger)

Claims (3)

A refrigerant circuit (2) to which a compressor (11), a use side heat exchanger (31), a heat source side heat exchanger (13), and an expansion mechanism (15, 17) are connected;
Carbon dioxide refrigerant filled in the refrigerant circuit (2);
A lubricating oil mainly filled in the compressor (11);
An acid neutralizer mixed in the lubricating oil;
A refrigeration apparatus (1). The acid neutralizing agent is a basic detergent.
The refrigeration apparatus (1) according to claim 1. The acid neutralizing agent is at least one basic detergent selected from the group consisting of sulfonates, phenates, salicylates and naphthenates;
The refrigeration apparatus (1) according to claim 2.

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