JP2010038380A - Refrigeration system and moisture removal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove water mixed in a refrigerant while preventing breakage of a refrigeration system and increase of costs. <P>SOLUTION: The refrigeration system 100 is equipped with a refrigerant circuit 10 and a separation part 21. The refrigeration circuit 10 can freeze the water included in the refrigerant while changing a state of the refrigerant by a refrigerating cycle. Specifically, the refrigeration circuit 10 includes a compressor 1, a heat exchanger 61 (62) functioning as a radiator, a pressure reducing mechanism 3, a radiator 62 (61) functioning as an evaporator, and piping 5 passing the refrigerant through them in this order. By controlling the refrigerant circuit 10, a temperature of the refrigerant is lowered to a freezing point of water or less. The separation part 21 separates the water frozen by the refrigerant circuit 10 from the refrigerant. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration system and a water removal device, and more particularly, to one using carbon dioxide as a refrigerant.

  When carbon dioxide (CO2) is used as a refrigerant in a refrigeration system, water is often mixed into carbon dioxide. When water is contained in carbon dioxide, water and carbon dioxide react with each other in the refrigeration cycle to generate carbonic acid. Then, copper used as the material of the piping reacts with carbonic acid, and copper ions are eluted from the inner wall of the piping to the 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 system 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.

  Therefore, techniques for removing water contained in carbon dioxide 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 system 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 carbon dioxide. 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.

Further, the refrigeration system described in Patent Document 2 requires costs such as drying and vacuuming in the manufacturing process. Further, in a large-capacity refrigeration system, 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 system and a moisture removal device that can remove moisture mixed in a refrigerant without damaging the refrigeration system and suppress an increase in cost.

  The refrigeration system according to the first invention includes a refrigerant circuit and a separation unit. The refrigerant circuit can freeze water contained in the refrigerant while changing the state of the refrigerant by the refrigeration cycle. The separation unit separates water frozen in the refrigerant circuit from the refrigerant.

  A refrigeration system according to a second aspect is the refrigeration system according to the first aspect, wherein the refrigerant circuit functions as a compressor, a first heat exchanger that functions as a radiator, a pressure reducing mechanism, and an evaporator. It has a 2nd heat exchanger and piping which flows a refrigerant | coolant in this order.

  A refrigeration system according to a third aspect of the present invention is the refrigeration system according to the second aspect of the present invention, wherein the separation unit is detachably disposed on the pipe.

  A refrigeration system according to a fourth aspect of the present invention is the refrigeration system according to the second aspect of the present invention, further comprising a pipe and a selection mechanism. The pipe bypasses a part of the pipe through the separation part. The selection mechanism can selectively cause the refrigerant to flow through one of the pipe and the pipe.

  A refrigeration system according to a fifth aspect of the present invention is the refrigeration system according to any one of the second to fourth aspects of the present invention, wherein the separation unit depressurizes the first heat exchanger and the compressor in the pipe. It arrange | positions in the part connected via a mechanism and a 2nd heat exchanger.

  A refrigeration system according to a sixth aspect of the present invention is the refrigeration system according to any one of the first to fifth aspects of the present invention, and the separation unit can be reused.

  A refrigeration system according to a seventh aspect is the refrigeration system according to any one of the first to sixth aspects, wherein the refrigerant contains carbon dioxide as a main component.

  A water removal apparatus according to an eighth aspect of the present invention is an apparatus for removing water contained in a refrigerant, and includes a generation unit and a separation unit. A production | generation part produces | generates ice from water. The separation unit separates the ice from the refrigerant.

  According to the refrigeration system according to the first invention, moisture in the refrigerant can be removed. In addition, since there is no need to use a desiccant or the like, there is no influence on the refrigeration cycle accompanying the removal of moisture. Moreover, since the water | moisture content in a refrigerant | coolant can be removed with the simple means of freezing of water and isolation | separation, the increase in cost can be prevented. Furthermore, since a refrigerant circuit capable of performing a normal refrigeration cycle can be used for freezing water, it is not necessary to separately provide a device for generating ice, and the refrigeration system can be simplified.

  According to the refrigeration system according to the second invention, in the refrigerant circuit, the water contained in the refrigerant can be frozen while changing the state of the refrigerant by the refrigeration cycle.

  According to the refrigeration system according to the third aspect of the present invention, since the separation unit is removable, it is possible to prevent the ice separated by the separation unit from returning to the refrigerant again by removing the separation unit after removing moisture. .

  According to the refrigeration system according to the fourth aspect of the invention, the refrigerant can be guided to the separation unit by flowing the refrigerant toward the pipe by the selection mechanism. In addition, after the ice is separated by the separation unit, the refrigerant is allowed to flow toward a part of the pipe by the selection mechanism, so that the refrigeration cycle can be executed using the refrigerant from which moisture has been removed.

  According to the refrigeration system according to the fifth aspect of the present invention, it is easy to freeze water contained in the refrigerant in the portion where the piping is applied.

  According to the refrigeration system according to the sixth aspect of the present invention, the cost for removing moisture in the refrigerant can be reduced by reusing the separation unit.

  According to the refrigeration system according to the seventh aspect of the present invention, it is easy to remove moisture in the refrigerant by employing a refrigerant containing carbon dioxide as a main component.

  According to the moisture removing apparatus of the eighth invention, moisture in the refrigerant can be removed. In addition, since there is no need to use a desiccant or the like, there is no influence on the refrigeration cycle accompanying moisture removal. Moreover, since the water | moisture content in a refrigerant | coolant can be removed with the simple means of production | generation and isolation | separation of ice, the increase in cost can be prevented.

  FIG. 1 is a conceptual diagram of a refrigeration system according to an embodiment of the present invention. In FIG. 1, the refrigeration system 100 includes a refrigerant circuit 10 and a separation unit 21.

<Refrigerant circuit 10>
(Configuration of refrigerant circuit 10)
The refrigerant circuit 10 can freeze water contained in the refrigerant while changing the state of the refrigerant by a vapor compression refrigeration cycle. Specifically, the refrigerant circuit 10 includes a compressor 1, heat exchangers 61 and 62, a four-way switching valve 8, a decompression mechanism 3, and a pipe 5. In addition, what contains a carbon dioxide as a main component is employ | adopted for a refrigerant | coolant.

  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 outside air, and the other functions as an evaporator that transfers heat from the outside air to the refrigerant. To do.

  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 a state of a refrigerant containing carbon dioxide as a main component. 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 to 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 transfers the heat of the refrigerant that has flowed into itself to the outside 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 changes 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.

  The evaporator increases the enthalpy of the refrigerant without changing the pressure by transferring heat from outside air to the refrigerant flowing into the evaporator. 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.

(Control of refrigerant circuit 10)
By performing the above-described refrigeration cycle, cooling and heating can be performed as normal operation (hereinafter referred to as “normal operation”). Moreover, when the temperature of the refrigerant falls below the freezing point of water in some state during the refrigeration cycle, the water in the refrigerant freezes for the refrigerant in that state.

  In the refrigeration cycle in normal operation, when no state appears where the temperature of the refrigerant is equal to or lower than the freezing point of water, for example, by controlling the refrigerant circuit 10 as follows, the temperature of the refrigerant is equal to or lower than the freezing point of water. (Hereinafter referred to as “freezing operation”).

  That is, by controlling the depressurization mechanism 3, the depressurization width at the time of transition from the state C to the state D (FIG. 2) is increased, and the temperature of the refrigerant is set to the freezing point of water or lower. Thereby, the temperature of the refrigerant | coolant in the state D becomes below the freezing point of water. Further, in the state between the state D and the state A in the refrigeration cycle, since the temperature of the refrigerant is substantially constant, the temperature of the refrigerant in the state between the state D and the state A is also below the freezing point of water. Become.

  According to the icing operation described above, the refrigerant flowing between the decompression mechanism 3 and the suction port 11 of the compressor 1 in the direction of the arrow 111 (112) through the heat exchanger 62 (61) functioning as an evaporator. The temperature can be made below the freezing point of water.

  Even in the state between the state C and the state D, the temperature of the refrigerant tends to be below the freezing point of water. That is, the temperature of the refrigerant flowing in the direction of the arrow 111 between the heat exchanger 61 (62) functioning as a radiator and the decompression mechanism 3 is likely to be below the freezing point of water. This is because state C and state D are located on the low temperature side in the phase diagram shown in FIG.

(Comparison of refrigerant saturation water content)
FIG. 3 is a graph showing the relationship between the temperature and the saturated moisture content when the state of the five refrigerants is liquid, and FIG. 4 shows the relationship between the temperature and the saturated moisture amount when the state of the five refrigerants is gas. It is a graph which shows the relationship.

  In FIG. 3, when the state of the refrigerant is liquid, the saturated moisture content of carbon dioxide (CO 2) is about ½ times that of R410A and is almost the same as other refrigerants. In FIG. 4, when the state of the refrigerant is a gas, the saturated water content of carbon dioxide (CO2) is about 1/3 to 1/5 times that of other refrigerants.

  3 and 4, it can be seen that the moisture in carbon dioxide (CO2) is more likely to be saturated than the moisture in other refrigerants. From this, it can be seen that in the refrigerant containing carbon dioxide as a main component, ice is likely to precipitate during the freezing operation.

<Separation part 21>
FIG. 5 is an enlarged view of the separation portion shown in FIG. 1 and the vicinity thereof. In FIG. 5, the separation unit 21 can separate the ice generated in the refrigerant circuit 10 from the refrigerant.

(Configuration of separation unit 21)
Specifically, the separation unit 21 includes a filter 211 that captures ice. As a result, the refrigerant flows in the separation unit 21, whereby the ice in the refrigerant is captured by the filter 211, and the ice is separated from the refrigerant. Therefore, moisture in the refrigerant can be removed.

  As the filter 211, a reusable filter or a replaceable filter is used. When a reusable filter is used for the filter 211, the cost for removing moisture in the refrigerant can be reduced.

(Arrangement position of separation part 21)
In view of the function of the separation part 21 for capturing ice, the separation part 21 is preferably disposed at a position where a refrigerant whose temperature is equal to or lower than the freezing point of water flows. That is, in the pipe 5, the heat exchanger 61 (62) functioning as a radiator and the suction port 11 of the compressor 1 are connected to the portion via the decompression mechanism 3 and the heat exchanger 62 (61). It is preferable to arrange the separation part 21.

  More preferably, the separation unit 21 is connected to a portion of the pipe 5 where the decompression mechanism 3 and the suction port 11 of the compressor 1 are connected via a heat exchanger 62 (61) functioning as an evaporator.

  In FIG. 1, when the four-way switching valve 8 is in the state a, the separation unit 21 is arranged in the pipe 5 that connects the heat exchanger 62 that functions as an evaporator and the suction port 11 of the compressor 1. The installed refrigeration system is shown.

  FIG. 6 is another conceptual diagram of the refrigeration system. When the four-way switching valve 8 is in the state b, the heat exchanger 62 that functions as a radiator and the pipe 5 that connects the decompression mechanism 3 are separated. The case where the part 21 is arrange | positioned is shown.

(Aspect of disposition of separation part 21)
The mode of arrangement | positioning of the isolation | separation part 21 is demonstrated using FIG.1 and FIG.5. The refrigeration system 100 further includes a tube 52 and a selection mechanism 22. The pipe 52 bypasses a part 51 of the pipe 5 via the separation part 21.

  The selection mechanism 22 can selectively cause the refrigerant to flow through either the part 51 of the pipe 5 or the pipe 52. Specifically, the selection mechanism 22 has on-off valves 221 and 222 (FIG. 5). The on-off valve 221 is disposed in a part 51 of the pipe 5 at a position near the connection point 511 on the upstream side in the direction of the arrow 111 among the connection points 511 and 512 between the pipe 5 and the pipe 52. The on-off valve 222 is disposed on the pipe 52 at a position near the connection point 511. As the on-off valves 221, 222, for example, a solenoid valve or the like is employed.

  Then, by closing the on-off valve 221 and opening the on-off valve 222, the refrigerant can flow toward the pipe 52. On the other hand, by opening the on-off valve 221 and closing the on-off valve 222, the refrigerant can flow toward the part 51 of the pipe 5.

  According to the above-described arrangement of the separation unit 21, the refrigerant can be guided to the separation unit 21 by flowing the refrigerant toward the pipe 52 by the selection mechanism 22. Moreover, after the ice is separated by the separation unit 21, the refrigeration cycle can be executed using the refrigerant from which moisture has been removed by causing the selection mechanism 22 to flow the refrigerant toward the part 51 of the pipe 5.

  In FIG. 5, the on-off valve 23 disposed on the pipe 52 at a position near the connection point 512 is also shown. When the refrigerant flows toward the part 51 of the pipe 5, it is preferable to close the on-off valve 23. This is to prevent the ice separated by the separation unit 21 from returning to the refrigerant flowing through the pipe 5 again.

  According to the refrigeration system 100 described above, moisture in the refrigerant can be removed. In addition, since there is no need to use a desiccant or the like, there is no influence on the refrigeration cycle accompanying the removal of moisture. Moreover, since the water | moisture content in a refrigerant | coolant can be removed with the simple means of freezing of water and isolation | separation, the increase in cost can be prevented.

  Furthermore, since the water in the refrigerant can be frozen using the refrigerant circuit 10 capable of normal operation, there is no need to separately provide a device for generating ice. It can be simplified.

<Modification 1>
The separation unit 21 may be detachably disposed on the pipe 5. According to this aspect, it is possible to prevent the ice separated by the separation unit 21 from returning to the refrigerant again by removing the separation unit 21 after removing moisture in the refrigerant.

  The separation unit 21 may be disposed directly and detachably on the part 51 of the pipe 5. Even in such an embodiment, it is possible to prevent the ice separated by the separation unit 21 from returning to the refrigerant again by removing the separation unit 21 after removing moisture in the refrigerant. However, after removing the separation part 21, it is necessary to connect the place where the separation part 21 existed with piping.

<Modification 2>
In the refrigeration system 100 described above, the water in the refrigerant is frozen using the refrigerant circuit 10, but a generating unit that generates ice from water may be provided separately from the refrigerant circuit 10. That is, the refrigeration system 100 may be configured by the refrigerant circuit 10 and the moisture removing device including the generation unit and the separation unit 21.

  Also in this aspect, the water | moisture content in a refrigerant | coolant can be removed similarly to the refrigeration system 100 mentioned above.

<Modification 3>
Although the refrigeration system 100 using the refrigerant containing carbon dioxide as a main component has been described above, the above-described technique can be applied to a refrigeration system using a refrigerant other than carbon dioxide as the refrigerant. Also in this case, moisture in the refrigerant can be removed.

  As described above, the present invention is useful for an air conditioner using a vapor compression refrigeration cycle.

The conceptual diagram of the refrigerating system which concerns on one Embodiment of this invention. The pressure-enthalpy diagram which shows the state of the carbon dioxide which is a refrigerant | coolant. The graph which shows the relationship between the temperature when a state is a liquid about 5 refrigerant | coolants, and saturated moisture content. The graph which shows the relationship between the temperature when a state is gas about five refrigerant | coolants, and saturated moisture content. FIG. 2 is an enlarged view of a separation unit shown in FIG. 1 and its vicinity. The other conceptual diagram of a refrigeration system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 3 Pressure reduction mechanism 5 Piping 10 Refrigerant circuit 21 Separation part 22 Selection mechanism 51 Part of piping 52 Pipes 61 and 62 Heat exchanger

Claims (8)

A refrigerant circuit (10) capable of freezing water contained in the refrigerant while changing a state of the refrigerant by a refrigeration cycle;
A separator (21) for separating water frozen in the refrigerant circuit (10) from the refrigerant;
With
Refrigeration system. The refrigerant circuit (10) includes a compressor (1), a first heat exchanger (61, 62) that functions as a radiator, a decompression mechanism (3), and a second heat exchange that functions as an evaporator. A vessel (62, 61) and a pipe (5) through which the refrigerant flows in this order,
The refrigeration system according to claim 1. The separation part (21) is detachably disposed on the pipe (5).
The refrigeration system according to claim 2. A pipe (52) for bypassing a part (51) of the pipe (5) via the separation part (21);
A selection mechanism (22) capable of selectively flowing the refrigerant through one of the part (51) and the pipe (52) of the pipe (5);
Further comprising
The refrigeration system according to claim 2. The separation unit (21) includes the first heat exchanger (61) and the compressor (1) in the pipe (5), the decompression mechanism (3), and the second heat exchanger. (62) disposed at the connecting portion,
The refrigeration system according to any one of claims 2 to 4. The separation part (21) can be reused.
The refrigeration system according to any one of claims 1 to 5. The refrigerant contains carbon dioxide as a main component,
The refrigeration system according to any one of claims 1 to 6. An apparatus for removing water contained in a refrigerant,
A generator for generating ice from the water;
A separator (21) for separating the ice from the refrigerant;
With
Moisture removal device.

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