JP2010038381A - Refrigeration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration system hardly causing breakage even if moisture is mixed in a refrigerant. <P>SOLUTION: The refrigeration system 100 is equipped with a refrigerant circuit 10, and a removal part 2. The refrigerant circuit 10 is a circuit carrying out a refrigerating cycle by using the refrigerant, and it includes a compressor 1, heat exchangers 61, 62, a four-way selector valve 8, a pressure reducing mechanism 3, and piping 5. A refrigerant including carbon dioxide as a main component is adopted. The removal part 2 removes copper ions included in the refrigerant flowing through the refrigerant circuit 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus, and in particular, to one using CO2 (carbon dioxide) as a refrigerant.

  When CO2 (carbon dioxide) is used as a refrigerant in a refrigeration apparatus, water is often mixed in CO2. When water is contained in CO2, in the refrigeration cycle, water and CO2 react to generate carbonic acid. And copper and carbonic acid used as piping react, and copper ion elutes from the inner wall of piping to a refrigerant.

  The eluted copper ions circulate together with the refrigerant, and the activated portion of the metal surface is plated with copper (copper plating phenomenon). In a refrigeration apparatus equipped with a compressor, a copper plating phenomenon tends to occur on the metal surface of the compression mechanism of the compressor.

  When the metal surface of the compression mechanism is plated with copper, a gap provided between the movable scroll and the fixed scroll constituting the compression mechanism is filled, and smooth sliding is prevented. Moreover, there is a possibility that the compressor may be damaged by copper fragments generated during sliding.

  Thus, techniques for removing water contained in CO2 have been proposed. For example, a technique for providing a desiccant such as molecular sieves in a pipe (see Patent Document 1), a technique for removing water in the refrigeration apparatus by drying or vacuuming (see Patent Document 2), and the like have been proposed. .

  However, in the molecular sieve described in Patent Document 1, it is difficult to capture water mixed in CO2. Further, when granular molecular sieves are used, the molecular sieves rub against each other and fine powder is generated. If fine powder enters the compression mechanism of the compressor, the compression mechanism may be damaged.

In the refrigeration apparatus described in Patent Document 2, a process such as drying and evacuation is required in the manufacturing process, which increases costs. Further, in a large-capacity refrigeration apparatus, the time required for drying and evacuation becomes longer, and the cost is further increased.
JP 2001-153501 A JP-A-9-256594

  An object of the present invention is to provide a refrigeration apparatus that is less likely to be damaged even when moisture is mixed in the refrigerant.

  The refrigeration apparatus according to the first invention includes a refrigerant circuit and a removal unit. The refrigerant circuit performs a refrigeration cycle using the refrigerant. The removing unit removes copper ions contained in the refrigerant flowing through the refrigerant circuit.

  A refrigeration apparatus according to a second aspect of the present invention is the refrigeration apparatus according to the first aspect of the present invention, wherein the removing unit has an ion electrode that contacts the refrigerant flowing through the refrigerant circuit.

  A refrigeration apparatus according to a third aspect of the present invention is the refrigeration apparatus according to the second aspect of the present invention, wherein the ion electrode is sealed with glass.

  A refrigeration apparatus according to a fourth aspect of the present invention is the refrigeration apparatus according to the first aspect of the present invention, wherein the removal unit is a catalyst that captures copper ions.

  A refrigeration apparatus according to a fifth aspect of the present invention is the refrigeration apparatus according to the fourth aspect of the present invention, wherein the catalyst is zeolite.

  A refrigeration apparatus according to a sixth invention is the refrigeration apparatus according to any one of the first to fifth inventions, wherein the refrigerant contains carbon dioxide as a main component.

  In the refrigeration apparatus according to the first aspect of the invention, the copper ions in the refrigerant are removed, so that the occurrence of a copper plating phenomenon can be prevented. Therefore, even when moisture is mixed in the refrigerant, the refrigeration apparatus is hardly damaged.

  In the refrigeration apparatus according to the second invention or the third invention, copper ions are attracted to the cathode side by generating a potential between the ion electrodes. Therefore, copper ions can be captured (removed) by the ion electrode.

  In the refrigeration apparatus according to the fourth invention or the fifth invention, copper ions can be captured (removed).

  In the refrigeration apparatus according to the sixth aspect of the invention, copper ions can be removed even if the refrigerant is carbon dioxide.

  FIG. 1 is a conceptual diagram of a refrigeration apparatus according to an embodiment of the present invention. In FIG. 1, the refrigeration apparatus 100 includes a refrigerant circuit 10 and a removal unit 2.

<Refrigerant circuit 10>
(Configuration of refrigerant circuit 10)
The refrigerant circuit 10 is a circuit that performs a refrigeration cycle using refrigerant, and includes a compressor 1, heat exchangers 61 and 62, a four-way switching valve 8, a decompression mechanism 3, and a pipe 5. A refrigerant containing CO2 as a main component is employed as the refrigerant.

  The compressor 1 has a suction port 11 and a discharge port 12, compresses the refrigerant sucked from the suction port 11, and discharges it from the discharge port 12.

  Both of the heat exchangers 61 and 62 exchange heat between external air and the refrigerant. Specifically, one of the heat exchangers 61 and 62 functions as a radiator that transfers heat from the refrigerant to the external air, and the other functions as an evaporator that transfers heat from the external air to the refrigerant.

  The four-way switching valve 8 has terminals 81 to 84, communicates the terminal 81 and the terminal 84, and communicates the terminal 82 and the terminal 83 (mode a), and communicates the terminal 81 and the terminal 82. And the aspect (mode b) which makes the terminal 83 and the terminal 84 communicate can be switched alternately.

  Terminals 81-84 are connected by piping 5 as follows. The terminal 81 is connected to the suction port 11 of the compressor 1. The terminal 82 is connected to one end 611 of the heat exchanger 61. The terminal 83 is connected to the discharge port 12 of the compressor 1. The terminal 84 is connected to one end 621 of the heat exchanger 62.

  The decompression mechanism 3 is connected between the other end 612 of the heat exchanger 61 and the other end 622 of the heat exchanger 62. The pipe 5 is also used to connect the decompression mechanism 3 to the other ends 612 and 622.

  According to the refrigerant circuit 10 described above, the refrigerant flows in the direction of the arrow 111 by switching the four-way switching valve 8 to the mode a. That is, the refrigerant flows in the order of the compressor 1, the heat exchanger 61, the decompression mechanism 3, and the heat exchanger 62. Therefore, the heat exchanger 61 can function as a radiator, and the heat exchanger 62 can function as an evaporator. When the heat exchanger 61 is disposed in the outdoor unit and the heat exchanger 62 is disposed in the indoor unit, the refrigerant circuit 10 functions as a cooling unit.

  On the other hand, the refrigerant flows in the direction of arrow 112 by switching the four-way switching valve 8 to the mode b. That is, the refrigerant flows in the order of the compressor 1, the heat exchanger 62, the decompression mechanism 3, and the heat exchanger 61. Therefore, the heat exchanger 61 can function as an evaporator, and the heat exchanger 62 can function as a radiator. When the heat exchanger 61 is disposed in the outdoor unit and the heat exchanger 62 is disposed in the indoor unit, the refrigerant circuit 10 functions as a heater.

(Refrigeration cycle)
FIG. 2 is a pressure-enthalpy diagram showing the state of the refrigerant contained as the main component of CO2. In FIG. 2, a critical point CP, a saturated vapor line 101, a saturated liquid line 102, and boundary lines 103 and 104 are shown. The saturated vapor line 101 indicates a boundary between a state in which a gas and a liquid are mixed (hereinafter referred to as “gas-liquid mixed state”) and a gas state. The saturated liquid line 102 indicates the boundary between the gas-liquid mixed state and the liquid state. The boundary line 103 is an isotherm passing through the critical point CP, and indicates a boundary between the liquid state and the supercritical state where the enthalpy is smaller than the critical point CP. The boundary line 104 is an isobaric line extending from the critical point CP toward the larger enthalpy and indicates the boundary between the gas state and the supercritical state. Hereinafter, the state of the circulating refrigerant will be described with reference to FIG.

  The compressor 1 compresses the refrigerant in a gaseous state (state A) and transfers it to the supercritical state (state B).

  The radiator moves the heat of the refrigerant that has flowed into itself to the external air, thereby reducing the enthalpy of the refrigerant with almost no change in pressure. As a result, the radiator transfers the refrigerant in the supercritical state (state B) to the liquid state (state C). At this time, a heat quantity Q substantially equal to the amount of change in enthalpy is given from the radiator to the air.

  The refrigerant in the supercritical state can change its temperature and pressure without latent heat. For this reason, heat can be efficiently obtained from the refrigerant in the supercritical state. Therefore, in the radiator in which the refrigerant state transitions from the supercritical state (state B) to the liquid state (state C), the external air is efficiently warmed.

  The decompression mechanism 3 transfers the refrigerant in the liquid state (state C) to the gas-liquid mixed state (state D) by reducing the pressure of the refrigerant flowing from the radiator side. At this time, the enthalpy of the refrigerant before and after passing through the decompression mechanism 3 hardly changes.

  An evaporator raises the enthalpy of the said refrigerant | coolant by moving a heat | fever from the external air to the refrigerant | coolant which flowed in itself, hardly changing a pressure. Thereby, an evaporator transfers the refrigerant | coolant in a gas-liquid mixing state (state D) to a gaseous state (state A). At this time, most of the heat obtained from the outside air is used as latent heat to change the state of the refrigerant.

<Removal unit 2>
FIG. 3 is a conceptual diagram of the removal unit. In FIG. 3, the removing unit 2 removes copper ions contained in the refrigerant flowing in the refrigerant circuit 10. Specifically, the removal unit 2 includes ion electrodes 21 and 22.

  One of the ion electrodes 21 and 22 is used as an anode, and the other is used as a cathode. An ion electrode 21 and an ion electrode 22 are connected to the anode side and the cathode side of a DC power source disposed outside the pipe 5, respectively.

  Both of the ion electrodes 21 and 22 are inserted into the pipe 5 from the side and are in contact with the refrigerant flowing through the refrigerant circuit 10. However, in the pipe 5, the ion electrodes 21 and 22 are separated from each other.

  In the removing unit 2, a potential is generated between the ion electrodes 21 and 22, and copper ions in the refrigerant are attracted to the cathode side. That is, since copper ions are attracted to the ion electrode 22 used as the cathode, they can be captured (removed) by the ion electrode 22. From the viewpoint of preventing the deterioration of the ion electrodes 21, 22, it is preferable to enclose each of the ion electrodes 21, 22 with glass 21a, 22a as shown in FIG.

  According to the refrigeration apparatus 100 described above, since copper ions in the refrigerant are removed, the occurrence of a copper plating phenomenon can be prevented. Therefore, even if moisture is mixed in the refrigerant, the refrigeration apparatus 100 is hardly damaged.

<Modification>
The removal unit 2 may be a catalyst that captures copper ions. For example, zeolite is used as the catalyst. Also in this modified example, since the copper ions in the refrigerant can be removed, the refrigeration apparatus 100 is hardly damaged even when moisture is mixed in the refrigerant.

  As described above, according to the present invention, even when water is mixed into the CO2 refrigerant and carbonic acid is generated and copper ions are eluted from the inner wall of the pipe to the refrigerant, the copper ions are captured by the ion electrode. Damage is unlikely to occur. Therefore, the present invention is useful for an air conditioner using a CO 2 refrigerant and a heat pump type hot water heater.

The conceptual diagram of the freezing apparatus which concerns on one Embodiment of this invention. The pressure-enthalpy diagram which shows the state of CO2 which is a refrigerant | coolant. The conceptual diagram of a removal part.

Explanation of symbols

2 Removal part 10 Refrigerant circuit 21, 22 Ion electrode 21a, 22a Glass

Claims (6)

A refrigerant circuit (10) for performing a refrigeration cycle using a refrigerant;
A removal section (2) for removing copper ions contained in the refrigerant flowing through the refrigerant circuit (10);
With
Refrigeration equipment. The removal unit (2) includes ion electrodes (21, 22) that are in contact with the refrigerant flowing through the refrigerant circuit (10).
The refrigeration apparatus according to claim 1. The ion electrodes (21, 22) are sealed with glass (21a, 22a),
The refrigeration apparatus according to claim 2. The removal unit (2) is a catalyst that captures the copper ions.
The refrigeration apparatus according to claim 1. The catalyst is a zeolite;
The refrigeration apparatus according to claim 4. The refrigerant contains carbon dioxide as a main component,
The refrigeration apparatus according to any one of claims 1 to 5.

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