JP6456088B2 - Radiator and refrigeration cycle device - Google Patents

Description

  The present invention relates to a radiator that radiates and cools a refrigerant that has been boosted to a supercritical pressure, and a refrigeration cycle apparatus that includes the radiator.

In general, a refrigeration cycle apparatus including a compressor that uses CO ₂ (carbon dioxide) as a refrigerant and boosts the refrigerant to a supercritical pressure, and a radiator that radiates and cools the refrigerant discharged from the compressor. It is known (see, for example, Patent Document 1). In this type of refrigeration cycle apparatus, a fin-and-tube type heat provided with a plurality of fin plates arranged at predetermined intervals as a radiator and a plurality of heat transfer tubes that are inserted through the fin plates and through which refrigerant flows. An exchanger is used to increase the efficiency of heat exchange. Conventionally, fin-and-tube heat exchangers are known that include a plurality of refrigerant flow paths formed in parallel to improve cooling (heating) capability (see, for example, Patent Document 2). ).

JP 2007-232365 A JP 07-208822 A

  By the way, in the configuration in which the pressure of the refrigerant is increased to the supercritical pressure, the refrigerant does not condense even when cooled by the radiator, and flows through the radiator as a gas refrigerant that undergoes a sensible heat change. In order to improve the coefficient of performance (COP) of the refrigeration cycle, it is desirable that the refrigerant outlet temperature in each refrigerant flow path of the radiator is lower.

  However, in the conventional configuration, the outlet heat transfer tube of one refrigerant flow path and the inlet heat transfer pipe of itself or another refrigerant flow path are arranged adjacent to each other, so that the refrigerant outlet is heated by the high-temperature refrigerant flowing through the inlet heat transfer pipe. There was a risk of temperature rise.

  This invention is made | formed in view of the situation mentioned above, and it aims at providing the heat radiator and the refrigerating-cycle apparatus which suppressed the raise of the refrigerant | coolant exit temperature of a refrigerant | coolant flow path.

  In order to solve the above-described problems and achieve the object, the present invention is a radiator that radiates the refrigerant whose pressure has been increased to a supercritical pressure, and is a plurality of radiators that extend in the vertical direction and are arranged at predetermined intervals. And a plurality of refrigerant flow paths formed in parallel by a heat transfer tube group that is inserted into the fin plate in multiple stages, and each of the plurality of refrigerant flow paths is provided at an inlet heat transfer pipe provided above the fin plate. And an outlet heat transfer tube provided below the fin plate, and an intermediate heat transfer tube provided between the inlet heat transfer tube and the outlet heat transfer tube.

  According to this configuration, each of the plurality of refrigerant flow paths is provided with the inlet heat transfer tube on the upper side of the fin plate and the outlet heat transfer tube on the lower side of the fin plate. The heat pipe and the inlet heat transfer pipe of itself or another refrigerant flow path can be arranged apart from each other. Furthermore, since the intermediate heat transfer tube is provided between the inlet heat transfer tube and the outlet heat transfer tube, the inlet heat transfer tube and the outlet heat transfer tube are not adjacent to each other. Therefore, since the refrigerant outlet temperature is prevented from rising due to the high-temperature refrigerant flowing through the inlet heat transfer tube, the coefficient of performance of the refrigeration cycle can be improved.

  In this configuration, the refrigerant flow paths may cause the refrigerant to flow from the upper heat transfer tube to the lower heat transfer tube, respectively. Although the refrigerant whose pressure has been increased to the supercritical pressure does not condense when passing through the radiator, the density (specific gravity) of the refrigerant gas increases with cooling. Therefore, by configuring the refrigerant flow path so that the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube, the flow of the refrigerant is promoted by gravity, and the heat exchange efficiency can be improved.

  In addition, a plurality of heat exchanging units divided into upper and lower portions may be provided, and the refrigerant flow may sequentially flow the refrigerant from the upper heat exchanging unit toward the lower heat exchanging unit. According to this configuration, since a temperature gradient is formed in which the temperature decreases from the upper heat exchanging part to the lower heat exchanging part, temperature unevenness in the radiator can be suppressed.

  The refrigerant flow path includes a first intermediate heat transfer pipe connected to the inlet heat transfer pipe and a second intermediate heat transfer pipe connected to the outlet heat transfer pipe, and the first intermediate heat transfer pipe and the second intermediate heat transfer pipe of each refrigerant flow path. An intermediate header to which all the heat pipes are connected may be provided. According to this configuration, even if the refrigerant distribution at the inlet heat transfer tube of the refrigerant flow path is inappropriate, the refrigerant is once collected in the intermediate header and then redistributed to each refrigerant flow path. Therefore, distribution can be made appropriate.

  The heat transfer tube group may be inserted into the fin plate in multiple rows and multiple stages, and the inlet heat transfer tubes may be arranged in a row on the leeward side of the outlet heat transfer tubes. According to this configuration, it is possible to suppress the influence of heat of air when heat is exchanged with the refrigerant, and it is possible to suppress an increase in the refrigerant outlet temperature. The refrigerant is preferably a carbon dioxide refrigerant.

  The refrigeration cycle apparatus of the present invention includes a refrigerant circuit in which the above-described radiator, a compressor that boosts the refrigerant to a supercritical pressure, a decompression device, and a load-side heat exchanger are connected by piping. According to this configuration, since the rise in the refrigerant outlet temperature of the radiator can be suppressed, a refrigeration cycle apparatus that improves the coefficient of performance of the refrigeration cycle can be realized.

  According to the present invention, each of the plurality of refrigerant channels has an inlet heat transfer tube provided on the upper side of the fin plate and an outlet heat transfer tube provided on the lower side of the fin plate. The heat pipe and the inlet heat transfer pipe of itself or another refrigerant flow path can be arranged apart from each other. Furthermore, since the intermediate heat transfer tube is provided between the inlet heat transfer tube and the outlet heat transfer tube, the inlet heat transfer tube and the outlet heat transfer tube are not adjacent to each other. Therefore, since the refrigerant outlet temperature is prevented from rising due to the high-temperature refrigerant flowing through the inlet heat transfer tube, the coefficient of performance of the refrigeration cycle can be improved.

FIG. 1 is a circuit configuration diagram of a refrigeration cycle apparatus according to the present embodiment. FIG. 2 is a Mollier diagram showing the refrigeration cycle of the refrigerant whose pressure has been increased to the supercritical pressure. FIG. 3 is a schematic diagram of a radiator according to the present embodiment. FIG. 4 is a schematic diagram of a radiator according to a modification. FIG. 5 is a schematic view of a radiator according to another embodiment. FIG. 6 is a schematic diagram of a radiator according to a modification. FIG. 7 is a schematic diagram of a radiator according to another modification.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited by the following embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

FIG. 1 is a circuit configuration diagram of a refrigeration cycle apparatus according to the present embodiment. As shown in FIG. 1, the refrigeration cycle apparatus 10 includes a refrigeration unit 11 and a load unit 12, and the refrigeration unit 11 and the load unit 12 are connected by a liquid refrigerant pipe 13 and a gas refrigerant pipe 14. A refrigerant circuit 15 for performing the refrigeration cycle operation is configured. The refrigerant circuit 15 uses carbon dioxide (CO ₂ ) refrigerant whose high pressure side is at a supercritical pressure. The carbon dioxide refrigerant is a useful refrigerant because it has the advantages that it has a low environmental burden, is not toxic and flammable, and is safe and inexpensive. It should be noted that other refrigerants can be used as long as the high pressure side becomes a supercritical pressure.

  The refrigerator unit 11 includes a compressor 16 that compresses a refrigerant. An oil separator 18, a gas cooler (radiator) 19, an expansion valve (a pressure reducing device) are disposed on the discharge side of the compressor 16 via a refrigerant discharge pipe 17. ) 20 are sequentially connected. A refrigerator-side liquid refrigerant pipe 30 through which liquefied refrigerant flows is connected to the outlet side of the expansion valve 20, and the refrigerator-side liquid refrigerant pipe 30 is connected to the liquid refrigerant pipe 13 described above. A refrigerant suction pipe 21 is connected to the suction side of the compressor 16, and the refrigerant suction pipe 21 is connected to the gas refrigerant pipe 14 described above via an accumulator (not shown).

  The compressor 16 includes a compression element 23 in the case 22. The compression element 23 is, for example, a two-stage compressible compression element including a low-stage compression element and a high-stage compression element, and compresses a low-pressure gas refrigerant sucked through the refrigerant suction pipe 21 to obtain a supercritical pressure. The high-temperature and high-pressure gas refrigerant whose pressure has been increased up to is discharged to the refrigerant discharge pipe 17. The compression element 23 is driven by an electric motor unit (not shown), and the rotation speed of the compression element 23 can be adjusted by changing the operating frequency of the electric motor unit. Further, in the case 22, oil for lubricating each part (bearing part and sliding part) of the compression element 23 is accommodated, and a sensor 29 for detecting the amount of oil in the case 22 is provided.

  The oil separator 18 separates and captures the oil contained in the high-pressure (supercritical pressure) gas refrigerant discharged from the compressor 16 from the refrigerant. The oil separator 18 includes an oil return pipe 24 that returns the captured oil to the case 22 of the compressor 16, and the oil return pipe 24 is connected to a refrigerant suction pipe 21 via an electromagnetic valve 25 and a capillary pipe (throttle) 26. It is connected to the. In the present embodiment, the electromagnetic valve 25 is opened and closed based on a signal from the sensor 29 that detects the oil amount.

  The gas cooler 19 performs heat exchange between the high-temperature and high-pressure (supercritical pressure) gas refrigerant discharged from the compressor 16 and the air, and dissipates the heat to cool the gas refrigerant. Although the gas cooler 19 will be described in detail later, the gas cooler 19 is constituted by a fin-and-tube heat exchanger, and a blower fan (not shown) for blowing air toward the gas cooler 19 is disposed on the side of the gas cooler 19. The expansion valve 20 depressurizes (expands) the cooled gas refrigerant to liquefy it.

  On the other hand, the load unit 12 includes a load side pipe 27 connecting the liquid refrigerant pipe 13 and the gas refrigerant pipe 14 and an evaporator (load side heat exchanger) 28 provided in the load side pipe 27. The load unit 12 cools the object by evaporating the liquid refrigerant supplied through the liquid refrigerant pipe 13 with the evaporator 28, and is used as a low-temperature freezer or a showcase. The evaporator 28 is configured by a fin-and-tube heat exchanger like the gas cooler 19, and a blower fan (not shown) for blowing air toward the evaporator 28 is disposed on the side of the evaporator 28. The evaporator 28 cools the air by removing heat from the blown air and evaporating the liquid refrigerant. The low-temperature and low-pressure gas refrigerant evaporated by the evaporator 28 is sucked into the compressor 16 through the gas refrigerant pipe 14, the accumulator, and the refrigerant suction pipe 21, and is compressed again by the compressor 16. In the present embodiment, the load unit 12 has been described with a configuration in which one evaporator 28 is provided, but a configuration in which a plurality of evaporators 28 are provided in parallel may be employed. In this case, it is preferable to provide the expansion valve 20 on each load side pipe 27 on the inlet side (liquid refrigerant pipe 13 side) of the evaporator 28.

  By the way, in the refrigeration cycle apparatus 10 of the present embodiment, since the refrigerant is pressurized to the supercritical pressure, the refrigerant does not condense even when cooled by the gas cooler 19, and the gas cooler 19 is a gas refrigerant that undergoes a sensible heat change. Circulate. FIG. 2 is a Mollier diagram showing the refrigeration cycle of the refrigerant whose pressure has been increased to the supercritical pressure. In FIG. 2, point A indicates the refrigerant pressure and enthalpy on the suction side of the compressor 16. Similarly, point B indicates the refrigerant pressure and enthalpy on the inlet side of the gas cooler 19, point C indicates the outlet side of the gas cooler 19, and point D indicates the refrigerant pressure and enthalpy on the inlet side of the evaporator 28. Moreover, the broken line in FIG. 2 shows each isotherm.

  As described above, the gas cooler 19 changes the sensible heat by cooling. In this case, as shown in FIG. 2, the amount of enthalpy from 120 ° C to 100 ° C, the amount of enthalpy from 100 ° C to 80 ° C, the amount of enthalpy from 80 ° C to 60 ° C, the amount of enthalpy from 60 ° C to about 35 ° C Are a, b, c, and d, respectively, the enthalpy amount is a <b <c <d. In particular, the enthalpy amount d from 60 ° C. to about 35 ° C. is larger than other temperature zones. Therefore, if the refrigerant outlet temperature in the gas cooler 19 is cooled to a lower temperature, the refrigeration effect can be increased correspondingly, and the coefficient of performance (COP) can be improved. Hereinafter, the configuration of the gas cooler 19 that can cool the refrigerant outlet temperature to a lower temperature will be described.

  FIG. 3 is a schematic diagram showing a gas cooler according to the present embodiment. As shown in FIG. 3, the gas cooler 19 extends in the vertical direction, and includes a plurality of fin plates 30 that are arranged substantially parallel to each other at intervals, and a plurality of heat transfer tubes that penetrate the fin plates 30. A heat tube group 33 is provided, and air flows in a direction perpendicular to the paper surface. In the present embodiment, the heat transfer tube groups 33 are arranged in one row and multiple stages (12 stages in this embodiment) in the vertical direction of the fin plate 30, and a plurality (three in this embodiment) of these heat transfer tube groups 33 are arranged. Refrigerant flow paths 34A, 34B, and 34C are formed in parallel. By forming a plurality of refrigerant flow paths, the refrigerant is distributed to the respective refrigerant flow paths, the flow rate flowing through each refrigerant flow path is reduced, and the flow path length of the refrigerant flow path is shortened. Pressure loss can be reduced and the coefficient of performance can be improved.

  The gas cooler 19 includes an inlet header 36 connected to the inlet pipe 35 (refrigerant discharge pipe 17) through the oil separator 18, and an outlet header 38 connected to the outlet pipe 37 (refrigerant discharge pipe 17) leading to the expansion valve 20. In addition, three refrigerant flow paths 34A, 34B, and 34C are formed between the inlet header 36 and the outlet header 38. The refrigerant flow paths 34A, 34B, 34C are each formed by connecting four heat transfer tubes, and the refrigerant flows from the upper side in the height direction (vertical direction) of the gas cooler 19 to the lower side.

  The refrigerant flow paths 34A, 34B, and 34C include inlet heat transfer tubes 40A, 40B, and 40C that are connected to the inlet header 36, respectively. These inlet heat transfer tubes 40 </ b> A, 40 </ b> B, 40 </ b> C are arranged on the upper portion (first, third, fifth) of the fin plate 30. The refrigerant flow paths 34A, 34B, and 34C include outlet heat transfer tubes 42A, 42B, and 42C connected to the outlet header 38, respectively. These outlet heat transfer tubes 42A, 42B, and 42C are arranged below the fin plate 30 (eight steps, ten steps, and twelve steps).

  The refrigerant flow path 34A includes a first intermediate heat transfer tube 41A1 connected to the inlet heat transfer tube 40A via the U-shaped tube 43, and a second intermediate heat transfer tube 41A2 connected to the outlet heat transfer tube 42A via the U-shaped tube 43. With. The first intermediate heat transfer tube 41A1 is arranged one step below the inlet heat transfer tube 40A, and the second intermediate heat transfer tube 41A2 is arranged one step above the outlet heat transfer tube 42A. The first intermediate heat transfer tube 41A1 and the second intermediate heat transfer tube 41A2 are connected by an intermediate header 44. Accordingly, in the refrigerant flow path 34A, the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube in the order of the inlet heat transfer tube 40A, the first intermediate heat transfer tube 41A1, the second intermediate heat transfer tube 41A2, and the outlet heat transfer tube 42A.

  Similarly, the refrigerant flow path 34B includes a first intermediate heat transfer pipe 41B1 connected to the inlet heat transfer pipe 40B via the U-shaped pipe 43, and a second intermediate line connected to the outlet heat transfer pipe 42B via the U-shaped pipe 43. And a heat transfer tube 41B2. The first intermediate heat transfer tube 41B1 is arranged one step below the inlet heat transfer tube 40B, and the second intermediate heat transfer tube 41B2 is arranged one step above the outlet heat transfer tube 42B. The first intermediate heat transfer tube 41B1 and the second intermediate heat transfer tube 41B2 are connected by the intermediate header 44 described above. Accordingly, in the refrigerant flow path 34B, the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube in the order of the inlet heat transfer tube 40B, the first intermediate heat transfer tube 41B1, the second intermediate heat transfer tube 41B2, and the outlet heat transfer tube 42B. The refrigerant flow path 34C includes a first intermediate heat transfer pipe 41C1 connected to the inlet heat transfer pipe 40C via the U-shaped pipe 43, and a second intermediate transfer pipe connected to the outlet heat transfer pipe 42C via the U-shaped pipe 43. And a heat pipe 41C2. The first intermediate heat transfer tube 41C1 is arranged one step below the inlet heat transfer tube 40C, and the second intermediate heat transfer tube 41C2 is arranged one step above the outlet heat transfer tube 42C. The first intermediate heat transfer tube 41C1 and the second intermediate heat transfer tube 41C2 are connected by the intermediate header 44 described above. Thus, in the refrigerant flow path 34C, the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube in the order of the inlet heat transfer tube 40C, the first intermediate heat transfer tube 41C1, the second intermediate heat transfer tube 41C2, and the outlet heat transfer tube 42C.

  The gas cooler 19 includes an upper heat exchanging unit 45 and a lower heat exchanging unit 46 that are divided into a plurality (two in this embodiment) in the height direction (vertical direction). The refrigerant flow paths 34A, 34B, and 34C are formed so as to flow through the upper heat exchange unit 45 and the lower heat exchange unit 46, respectively. Specifically, in the refrigerant flow path 34A, the inlet heat transfer tube 40A and the first intermediate heat transfer tube 41A1 are provided in the upper heat exchange unit 45, and the second intermediate heat transfer tube 41A2 and the outlet heat transfer tube 42A are interposed via the intermediate header 44. Is provided in the lower heat exchange section 46. Similarly, in the refrigerant flow path 34B, the inlet heat transfer tube 40B and the first intermediate heat transfer tube 41B1 are provided in the upper heat exchange unit 45, and the second intermediate heat transfer tube 41B2 and the outlet heat transfer tube 42B are provided in the lower heat exchange unit 46. ing. The refrigerant flow path 34C includes an inlet heat transfer tube 40C and a first intermediate heat transfer tube 41C1 provided in the upper heat exchange unit 45, and a second intermediate heat transfer tube 41C2 and an outlet heat transfer tube 42C provided in the lower heat exchange unit 46. Yes.

  Thus, in this configuration, the refrigerant flow paths 34A, 34B, 34C are provided with the inlet heat transfer tubes 40A, 40B, 40C on the upper side of the fin plate 30, respectively, and the outlet heat transfer tubes 42A on the lower side of the fin plate 30. , 42B, and 42C, 42A, 42B, and 42C of each refrigerant flow path 34A, 34B, and 34C are separated from the inlet heat transfer tubes 40A, 40B, and 40C of themselves or other refrigerant flow paths 34A, 34B, and 34C. Can be arranged. Further, the refrigerant flow paths 34A, 34B, 34C are respectively provided with first intermediate heat transfer tubes (intermediate heat transfer tubes) 41A1, 41B1, 41C1 between the inlet heat transfer tubes 40A, 40B, 40C and the outlet heat transfer tubes 42A, 42B, 42C. Since the second intermediate heat transfer tubes (intermediate heat transfer tubes) 41A2, 41B2, and 41C2 are provided, the inlet heat transfer tubes 40A, 40B, and 40C and the outlet heat transfer tubes 42A, 42B, and 42C are not adjacent to each other. Therefore, since the refrigerant outlet temperature is prevented from rising by the high-temperature (for example, 100 to 120 ° C.) refrigerant flowing through the inlet heat transfer tubes 40A, 40B, and 40C, the coefficient of performance of the refrigeration cycle can be improved.

  The refrigerant flow paths 34A, 34B, and 34C are respectively provided with inlet heat transfer tubes 40A, 40B, and 40C, first intermediate heat transfer tubes 41A1, 41B1, and 41C1, second intermediate heat transfer tubes 41A2, 41B2, and 41C2, and outlet heat transfer tubes 42A and 42B. , 42C, the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube. Although the refrigerant whose pressure has been increased to the supercritical pressure is not condensed by the gas cooler 19, the density (specific gravity) of the refrigerant gas increases with cooling. Therefore, by configuring the refrigerant flow paths 34A, 34B, and 34C so that the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube, the flow of the refrigerant is promoted by gravity, and the heat exchange efficiency can be improved. it can.

  In addition, since the refrigerant is gradually cooled from the upper heat transfer tubes to the lower heat transfer tubes, the refrigerant flow paths 34A, 34B, and 34C make the temperature difference between the refrigerants flowing through the adjacent heat transfer tubes equal to or lower than a predetermined temperature. And heat transfer between adjacent heat transfer tubes can be suppressed. Referring to the Mollier diagram of FIG. 2, in this embodiment, since the temperature difference between the inlet and outlet of the gas cooler 19 is 85 ° C., the temperature difference of the refrigerant flowing through the adjacent heat transfer tubes is suppressed to about 20 ° C. to 25 ° C. be able to. Further, since the temperature difference between the inlet and outlet of the gas cooler 19 is usually about 60 ° C., in this case, the temperature difference of the refrigerant flowing through the adjacent heat transfer tubes can be suppressed to about 15 ° C.

  The gas cooler 19 includes an upper heat exchanging portion 45 and a lower heat exchanging portion 46 that are divided into upper and lower portions, and the refrigerant flow paths 34A, 34B, and 34C are directed from the upper heat exchanging portion 45 to the lower heat exchanging portion 46, respectively. Therefore, a temperature gradient in which the temperature decreases from the upper heat exchanging portion 45 toward the lower heat exchanging portion 46 is formed, and the temperature unevenness of the gas cooler 19 can be suppressed.

  Further, the refrigerant flow paths 34A, 34B, 34C are respectively connected to the first intermediate heat transfer tubes 41A1, 41B1, 41C1 connected to the inlet heat transfer tubes 40A, 40B, 40C and the second intermediate transfer tubes connected to the outlet heat transfer tubes 42A, 42B, 42C, respectively. And an intermediate header 44 to which all the first intermediate heat transfer tubes 41A1, 41B1, 41C1 and the second intermediate heat transfer tubes 41A2, 41B2, 41C2 of the refrigerant flow paths 34A, 34B, 34C are connected. Therefore, even if the refrigerant distribution at the inlet heat transfer tubes 40A, 40B, and 40C of the refrigerant flow paths 34A, 34B, and 34C is inappropriate, the refrigerant is once collected in the intermediate header 44, Since it is redistributed to the refrigerant flow paths 34A, 34B, 34C, the distribution can be made appropriate. For this reason, heat exchange in the gas cooler 19 can be sufficiently performed.

  Next, a modification of this embodiment will be described. FIG. 4 is a schematic diagram showing a gas cooler according to a modification. In the gas cooler 50, the same components as those of the gas cooler 19 described above are denoted by the same reference numerals and description thereof is omitted. In the gas cooler 50, the refrigerant flow paths 34A, 34B, and 34C are connected to the first intermediate heat transfer tubes 41A1, 41B1, and 41C1 and the second intermediate heat transfer tubes 41A2, 41B2, and 41C2 through connecting tubes 47A, 47B, and 47C, respectively. ing. In this configuration, since the intermediate header 44 is not necessary, the gas cooler 50 can be downsized.

  In the above-described embodiment, each of the refrigerant flow paths 34A, 34B, and 34C includes two first heat transfer tubes 41A1, 41B1, and 41C1 and second intermediate heat transfer tubes 41A2, 41B2, and 41C2 as intermediate heat transfer tubes. However, the number may be changed as appropriate in accordance with the refrigerant flow rate and the size of the fin plate 30. It is sufficient that at least one intermediate heat transfer tube is provided, and the refrigerant flow path may have a minimum configuration in which the refrigerant flow flows one and a half times by three of the inlet heat transfer tube, the intermediate heat transfer tube, and the outlet heat transfer tube. In this configuration, the refrigerant outlet is located on the opposite side of the refrigerant inlet in the direction in which the heat transfer tube extends. When the refrigerant flow path is configured in three passes in this way, the temperature difference between the inlet and the outlet of the gas cooler 19 is 85 ° C. (FIG. 2), so the temperature difference between the refrigerants flowing through the adjacent heat transfer tubes is 25 ° C. to 30 ° C. It can be suppressed to about ℃. In this configuration, the temperature difference between the refrigerants flowing through the adjacent heat transfer tubes is higher than that in which the above-described refrigerant flow path is formed by four heat transfer tubes (four paths), and it may be about 30 ° C. It is done. In addition, since the inlet / outlet temperature difference of the gas cooler 19 is normally about 60 ° C., in this case, the temperature difference of the refrigerant flowing through the adjacent heat transfer tubes can be suppressed to about 20 ° C.

  In the above-described embodiment, the interval (pitch) at which the heat transfer tubes are arranged is the same. For example, the first intermediate heat transfer tube of the refrigerant flow path 34C between the upper heat exchange unit 45 and the lower heat exchange unit 46 is used. The space between 41C1 and the second intermediate heat transfer tube 41A2 of the refrigerant flow path 34A may be increased by an extra line. In this configuration, since heat transfer between the upper heat exchanging portion 45 and the lower heat exchanging portion 46 is suppressed, an increase in the refrigerant outlet temperature can be further suppressed.

  Next, a gas cooler according to another embodiment will be described. FIG. 5 is a schematic view showing a gas cooler according to another embodiment. In the above-described embodiment, the gas coolers 19 and 50 are configured to include one row of heat transfer tube groups 33, but in this embodiment, the configurations are different in that they include a plurality of rows of heat transfer tube groups 33. The same components as those of the gas cooler 19 described above are denoted by the same reference numerals and description thereof is omitted.

  The gas cooler 60 includes a heat transfer tube group 33 formed by heat transfer tubes in multiple rows and multiple stages (in this embodiment, two rows and six stages). The heat transfer tube group 33 is formed with different height positions of the heat transfer tubes in each row, and the heat transfer tubes in the leeward row are arranged slightly above the heat transfer tubes in the leeward row. The gas cooler 60 includes three refrigerant flow paths 34 </ b> A, 34 </ b> B, and 34 </ b> C formed in parallel by the heat transfer tube group 33.

  The refrigerant flow paths 34A, 34B, and 34C include inlet heat transfer tubes 40A, 40B, and 40C that are connected to the inlet header 36, respectively. These inlet heat transfer tubes 40 </ b> A, 40 </ b> B, 40 </ b> C are arranged in the upper part (first stage, second stage, third stage) of the leeward side row of the fin plate 30. The refrigerant flow paths 34A, 34B, and 34C include outlet heat transfer tubes 42A, 42B, and 42C connected to the outlet header 38, respectively. These outlet heat transfer tubes 42 </ b> A, 42 </ b> B, 42 </ b> C are arranged in the lower part (4th, 5th, 6th) of the windward row of the fin plate 30.

  The refrigerant flow path 34A is connected to the inlet heat transfer tube 40A via a U-shaped tube (not shown) and to the outlet heat transfer tube 42A via a U-shaped tube (not shown). A second intermediate heat transfer tube 41A2. The first intermediate heat transfer tube 41A1 is arranged at the uppermost stage of the row adjacent to the inlet heat transfer tube 40A (windward row), and the second intermediate heat transfer tube 41A2 is the row adjacent to the outlet heat transfer tube 42A (rowward side row). ) Below (four steps). The first intermediate heat transfer tube 41A1 and the second intermediate heat transfer tube 41A2 are connected by an intermediate header 44. Accordingly, in the refrigerant flow path 34A, the refrigerant flows from the upper heat transfer tube to the lower heat transfer tube in the order of the inlet heat transfer tube 40A, the first intermediate heat transfer tube 41A1, the second intermediate heat transfer tube 41A2, and the outlet heat transfer tube 42A.

  The refrigerant flow path 34B is connected to the inlet heat transfer tube 40B via a U-shaped tube (not shown) and to the outlet heat transfer tube 42B via a U-shaped tube (not shown). A second intermediate heat transfer tube 41B2. The first intermediate heat transfer tube 41B1 is arranged at the upper part (two stages) of the row adjacent to the inlet heat transfer tube 40B (windward row), and the second intermediate heat transfer tube 41B2 is positioned next to the outlet heat transfer tube 42B (downwind). (5 columns) at the bottom of the side column. The refrigerant flow path 34C is connected to the inlet heat transfer tube 40C via a U-shaped tube (not shown) and to the outlet heat transfer tube 42C via a U-shaped tube (not shown). Second intermediate heat transfer tube 41C2. The first intermediate heat transfer tube 41C1 is arranged in the upper part (three stages) of the row next to the inlet heat transfer tube 40C (upstream row), and the second intermediate heat transfer tube 41C2 is arranged next to the outlet heat transfer tube 42C (downwind) Side column) is arranged at the lower part (six levels). Thus, the refrigerant flow paths 34B and 34C are arranged in the order of the inlet heat transfer tubes 40B and 40C, the first intermediate heat transfer tubes 41B1 and 41C1, the second intermediate heat transfer tubes 41B2 and 41C2, and the outlet heat transfer tubes 42B and 42C, respectively. The refrigerant flows from the bottom to the lower heat transfer tube.

  The gas cooler 60 includes an upper heat exchange unit 45 and a lower heat exchange unit 46 which are divided into two in the height direction (vertical direction). The refrigerant flow paths 34A, 34B, and 34C are formed so as to flow through the upper heat exchange unit 45 and the lower heat exchange unit 46, respectively. Specifically, in the refrigerant flow path 34A, the inlet heat transfer tube 40A and the first intermediate heat transfer tube 41A1 are provided in the upper heat exchange unit 45, and the second intermediate heat transfer tube 41A2 and the outlet heat transfer tube 42A are interposed via the intermediate header 44. Is provided in the lower heat exchange section 46. Similarly, in the refrigerant flow path 34B, the inlet heat transfer tube 40B and the first intermediate heat transfer tube 41B1 are provided in the upper heat exchange unit 45, and the second intermediate heat transfer tube 41B2 and the outlet heat transfer tube 42B are provided in the lower heat exchange unit 46. ing. The refrigerant flow path 34C includes an inlet heat transfer tube 40C and a first intermediate heat transfer tube 41C1 provided in the upper heat exchange unit 45, and a second intermediate heat transfer tube 41C2 and an outlet heat transfer tube 42C provided in the lower heat exchange unit 46. Yes.

  In this embodiment, the heat transfer tube group 33 is inserted into the fin plate 30 in two rows and six stages, and the inlet heat transfer tubes 40A, 40B, and 40C of the refrigerant flow paths 34A, 34B, and 34C are connected to the outlet heat transfer tubes 42A, 42B, Since it is arranged in a row on the leeward side than 42C, it is possible to suppress the influence of the heat of the air when heat is exchanged with the refrigerant flowing through the heat transfer tubes, and it is possible to suppress an increase in the refrigerant outlet temperature.

  Next, a modification of this embodiment will be described. 6 and 7 are schematic views showing a gas cooler according to a modification. In these gas coolers 65 and 70, the same components as those of the gas coolers 19 and 60 described above are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 6, in the gas cooler 65, the refrigerant flow paths 34A, 34B, and 34C include the first intermediate heat transfer tubes 41A1, 41B1, and 41C1 and the second intermediate heat transfer tubes 41A2, 41B2, and 41C2, respectively. , 51C. In this configuration, the intermediate header 44 is not necessary, so that the gas cooler 65 can be downsized.

  In addition, the inlet heat transfer tubes 40A, 40B, and 40C and the outlet heat transfer tubes 42A, 42B, and 42C are not adjacent to each other, and the refrigerant flow paths 34A, 34B, and 34 flow the refrigerant from the upper heat transfer tube to the lower heat transfer tube, respectively. If it is comprised, the arrangement | positioning structure of each heat exchanger tube can be changed suitably. For example, in the gas cooler 70, as shown in FIG. 7, the inlet heat transfer tubes 40A, 40B, and 40C are not all provided in the leeward row, but the single inlet heat transfer tube 40B is placed at the uppermost stage in the leeward row. May be provided. Further, the outlet heat transfer tubes 42A, 42B, and 42C do not have to be provided in the leeward row, and one outlet heat transfer tube 42B may be provided in the lowermost row of the leeward row. Similarly to the gas cooler 65 described above, the gas cooler 70 according to this modification connects the first intermediate heat transfer tubes 41A1, 41B1, 41C1 and the second intermediate heat transfer tubes 41A2, 41B2, 41C2 without providing the intermediate header 44. They are connected via 52A, 52B, and 52C. Also in this configuration, an intermediate header 44 may be provided instead of the connecting pipes 52A, 52B, and 52C.

DESCRIPTION OF SYMBOLS 10 Refrigeration cycle apparatus 15 Refrigerant circuit 16 Compressor 19, 50, 60, 65, 70 Gas cooler (heat radiator)
20 Expansion valve (pressure reduction device)
28 Evaporator (load-side heat exchanger)
30 Fin plate 33 Heat transfer tube group 34A, 34B, 34C Refrigerant flow path 36 Inlet header 38 Outlet header 40A, 40B, 40C Inlet heat transfer tube 41A1, 41B1, 41C1 First intermediate heat transfer tube (intermediate heat transfer tube)
41A2, 41B2, 41C2 Second intermediate heat transfer tube (intermediate heat transfer tube)
42A, 42B, 42C Outlet heat transfer tube 44 Intermediate header 45 Upper heat exchange part (heat exchange part)
46 Lower heat exchange section (heat exchange section)

Claims (7)

A radiator that dissipates refrigerant that has been boosted to supercritical pressure,
A plurality of fin plates extending in the vertical direction and arranged at a predetermined interval; and a plurality of refrigerant flow paths formed in parallel by heat transfer tube groups inserted into the fin plates in multiple stages,
The plurality of refrigerant flow paths are respectively provided between an inlet heat transfer tube provided at an upper portion of the fin plate, an outlet heat transfer tube provided at a lower portion of the fin plate, and the inlet heat transfer tube and the outlet heat transfer tube. A first intermediate heat transfer tube connected to the inlet heat transfer tube via a U-shaped tube, and a second intermediate heat transfer tube connected to the outlet heat transfer tube via a U-shaped tube. And a configuration comprising
Below the inlet heat transfer tube and the first intermediate heat transfer tube of one refrigerant flow path, the inlet heat transfer tube and the first intermediate heat transfer tube of another refrigerant flow path are provided,
A heat radiator, wherein the second intermediate heat transfer tube and the outlet heat transfer tube of another refrigerant flow path are provided below the second intermediate heat transfer tube and the outlet heat transfer pipe of one refrigerant flow path .   2. The radiator according to claim 1, wherein each of the refrigerant flow paths causes the refrigerant to flow from an upper heat transfer tube to a lower heat transfer tube. It has a plurality of heat exchanging parts divided into upper and lower parts,
3. The radiator according to claim 1, wherein each of the refrigerant flow paths sequentially causes the refrigerant to flow from an upper heat exchange section toward a lower heat exchange section. The radiator according to any one of claims 1 to 3, further comprising an intermediate header to which the first intermediate heat transfer tube and the second intermediate heat transfer tube of each refrigerant channel are all connected. The heat transfer tube group is inserted into the fin plate in multiple rows and multiple stages, and the inlet heat transfer tube and the second intermediate heat transfer tube are arranged in a row on the leeward side of the first intermediate heat transfer tube and the outlet heat transfer tube , respectively. It arrange | positions, The heat radiator as described in any one of Claims 1-4 characterized by the above-mentioned.   The radiator according to any one of claims 1 to 5, wherein the refrigerant is a carbon dioxide refrigerant.   A radiator circuit comprising: the radiator according to any one of claims 1 to 6; a compressor that boosts a refrigerant to a supercritical pressure; a decompressor; and a load-side heat exchanger. A refrigeration cycle device.

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