JP2014126284A - Refrigeration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration device capable of reducing the performance degradation of a heat exchanger that functions as a cooler.SOLUTION: An air conditioner comprises: a compression mechanism; a first heat exchanger; and a second heat exchanger. The compression mechanism includes a low-stage compression unit; and a high-stage compression unit connected in series to the low-stage compression unit. The first heat exchanger comprises: a heat exchange unit; and a first left header 42. The heat exchange unit includes a plurality of paths in which refrigerant diverges and circulates. The first left header 42 is common to the paths. The first heat exchanger functions as a cooler that cools intermediate-pressure refrigerant between the low-stage compression unit and the high-stage compression unit. A second intermediate refrigerant tube is connected to the first left header 42. A tip end portion 85 of a connected portion 83 of the second intermediate refrigeration tube which portion is connected to the first left header 42 is formed into a tapered shape for which an opening area on an inner surface gradually increases.

Description

  The present invention relates to a refrigeration apparatus.

  Conventionally, a compression mechanism having a low-stage compression unit that compresses low-pressure refrigerant into an intermediate-pressure refrigerant and a high-stage compression unit that compresses intermediate-pressure refrigerant into a high-pressure refrigerant, and a low-stage compression unit and a high-stage compression unit And a means for cooling the intermediate pressure refrigerant.

  For example, the refrigeration apparatus disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-133581) includes a heat source side heat exchanger and an intermediate cooler as heat source units, and heat source side heat exchange during cooling operation. The cooler functions as a gas cooler, and the intermediate cooler cools the intermediate pressure refrigerant discharged from the low-stage compression element corresponding to the low-stage compression section and sucked into the high-stage compression element corresponding to the high-stage compression section. Functions as a cooler. In this refrigeration apparatus, the operation efficiency of the refrigeration apparatus is increased by cooling the intermediate pressure refrigerant in the middle of compression.

  By the way, the problem that the performance of a heat exchanger falls because the pressure loss of the refrigerant | coolant in the heat exchanger used as a cooler which cools the intermediate pressure refrigerant | coolant between a low stage compression part and a high stage compression part becomes large. There is.

  Then, the subject of this invention is providing the refrigeration apparatus which can reduce the performance fall of the heat exchanger which functions as a cooler.

  The refrigeration apparatus according to the first aspect of the present invention includes a compression mechanism, a heat exchanger, and piping. The compression mechanism includes a low-stage compression unit and a high-stage compression unit connected in series with the low-stage compression unit. The heat exchanger has a heat exchange part and a refrigerant header. The heat exchange unit has a plurality of paths through which the refrigerant branches and flows. The refrigerant header is common to a plurality of passes. The heat exchanger functions as a cooler that cools the intermediate pressure refrigerant between the low-stage compression unit and the high-stage compression unit. The piping is connected to the refrigerant header. Furthermore, the front-end | tip part of the connection part with the refrigerant | coolant header of piping is formed in the taper shape which the opening area of the inner surface expands gradually.

  In the refrigeration apparatus according to the first aspect of the present invention, the tip end portion of the connection portion of the pipe with the refrigerant header is formed in a tapered shape in which the opening area of the inner surface gradually increases. For this reason, the hole diameter of the connection part with the refrigerant | coolant header of piping can be enlarged. Therefore, in this refrigeration apparatus, the pressure loss of the refrigerant at the connection portion between the pipe and the refrigerant header can be reduced.

  As a result, it is possible to reduce the performance deterioration of the heat exchanger functioning as a cooler.

  The refrigerating apparatus according to the second aspect of the present invention is the refrigerating apparatus according to the first aspect, wherein the refrigerant header has an opening. An opening for connecting a pipe is formed in the opening. The opening includes an abutting surface against which the tip of the tip end abuts. For this reason, when connecting piping to a refrigerant | coolant header, positioning of piping can be made easy.

  The refrigeration apparatus according to the third aspect of the present invention is the refrigeration apparatus according to the second aspect, wherein the tip is located inside the virtual outer surface of the opening. For this reason, the fall of the pressure-resistant intensity | strength of a refrigerant | coolant header can be reduced.

  In the refrigeration apparatus according to the fourth aspect of the present invention, in the refrigeration apparatus according to any one of the first to third aspects, the taper tip edge of the tip portion coincides with the opening edge formed on the abutting surface, or , Located outside the opening edge. For this reason, compared with the case where a taper front-end edge exists inside the opening edge of a refrigerant | coolant header, it becomes difficult to become resistance of the flow of a refrigerant | coolant.

  In the refrigeration apparatus according to the fifth aspect of the present invention, in the refrigeration apparatus according to the first to fourth aspects, the refrigerant flows from the refrigerant header side toward the piping side. For this reason, the pressure loss of the refrigerant | coolant in the exit side of a heat exchanger can be reduced.

  In the refrigeration apparatus according to the sixth aspect of the present invention, in the refrigeration apparatus according to any one of the first to fifth aspects, when the heat exchanger functions as an evaporator, the refrigeration apparatus is directed from the pipe side toward the refrigerant header side. Phase refrigerant flows. In this refrigeration apparatus, the heat exchanger can function as an evaporator.

  In the refrigeration apparatus according to the first aspect of the present invention, it is possible to reduce the performance degradation of the heat exchanger that functions as a cooler.

  In the refrigeration apparatus according to the second aspect of the present invention, the piping can be easily positioned when the piping is connected to the refrigerant header.

  In the refrigeration apparatus according to the third aspect of the present invention, it is possible to reduce a decrease in pressure resistance of the refrigerant header.

  In the refrigeration apparatus according to the fourth aspect of the present invention, it becomes difficult for the refrigerant to flow.

  In the refrigeration apparatus according to the fifth aspect of the present invention, the pressure loss of the refrigerant on the outlet side of the heat exchanger can be reduced.

  In the refrigeration apparatus according to the sixth aspect of the present invention, the heat exchanger can function as an evaporator.

The schematic refrigerant circuit figure of the freezing apparatus which concerns on this invention. The schematic diagram of a heat exchange unit. The figure for demonstrating the flow of the refrigerant | coolant in a 1st heat exchanger. The top view of a 1st heat exchanger. The fragmentary sectional view of the 1st right side header periphery cut | disconnected in the horizontal direction. The fragmentary sectional view of the 1st left side header periphery cut | disconnected in the horizontal direction. The figure for demonstrating the flow of the refrigerant | coolant in a 2nd heat exchanger. The top view of the 2nd heat exchanger. The fragmentary sectional view around the 2nd left-hand header cut | disconnected in the horizontal direction. The fragmentary sectional view of the return header periphery cut | disconnected in the horizontal direction. Schematic diagram of the return header. The fragmentary sectional view of the 1st left-hand side header. The fragmentary sectional view of the lower periphery of a 1st heat exchanger. The fragmentary sectional view of the lower periphery of a 1st heat exchanger. The figure which looked at the section of the lower part circumference of the 1st heat exchanger from the side. The refrigerant | coolant pressure-enthalpy diagram in which the refrigerating cycle at the time of air_conditionaing | cooling operation was illustrated. The refrigerant | coolant temperature-entropy diagram by which the refrigerating cycle at the time of air_conditionaing | cooling operation was illustrated. The refrigerant | coolant pressure-enthalpy diagram in which the refrigerating cycle at the time of heating operation was illustrated. The refrigerant temperature-entropy diagram in which the refrigerating cycle at the time of heating operation was illustrated. The figure for demonstrating the pipe joint which concerns on a comparative example. The figure which shows the ratio of the pressure loss which a pipe joint occupies with respect to the pressure loss of the whole 1st heat exchanger when the pipe joint which concerns on this invention and a comparative example is used. The figure for demonstrating the pipe joint which concerns on the modification A. FIG.

  Hereinafter, an embodiment of an air conditioner 90 as an example of a refrigeration apparatus according to the present invention will be described based on the drawings.

(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 90 as an example of a refrigeration apparatus including a heat exchange unit 94 according to the present invention.

  The air conditioner 90 has a refrigerant circuit 10 configured to be capable of switching between a cooling operation and a heating operation, and uses a refrigerant (in this embodiment, carbon dioxide) that operates in a supercritical region, and is a two-stage compression type. An apparatus for performing a refrigeration cycle.

  The refrigerant circuit 10 of the air conditioner 90 mainly includes a compression mechanism 92, a switching mechanism 93, a heat exchange unit 94 (first heat exchanger 40 and second heat exchanger 60), an expansion mechanism 95, and a use side. And a heat exchanger 96. Hereinafter, the components of the refrigerant circuit 10 will be described.

(2) Components of Refrigerant Circuit (2-1) Compression Mechanism The compression mechanism 92 is composed of a compressor that compresses refrigerant in two stages with two compression elements. Specifically, the compression mechanism 92 has a sealed structure in which the compression mechanism drive motor 22, the drive shaft 23, the low-stage compression unit 92a, and the high-stage compression unit 92b are accommodated in the casing 21. Yes.

  The compression mechanism drive motor 22 is connected to the drive shaft 23. Further, the drive shaft 23 is connected to the low-stage compression unit 92a and the high-stage compression unit 92b. That is, in the compression mechanism 92, a low-stage compression unit 92a and a high-stage compression unit 92b are connected to a single drive shaft 23, and both the low-stage compression unit 92a and the high-stage compression unit 92b are compression mechanism drive motors. 22 is a so-called uniaxial two-stage compression structure that is driven by rotation.

  The low-stage compression section 92a and the high-stage compression section 92b are volumetric compression elements such as a rotary type and a scroll type, and the high-stage compression section 92b and the low-stage compression section 92a are connected in series. Then, the compression mechanism 92 sucks the refrigerant from the suction pipe 11, compresses the sucked refrigerant by the low-stage compression unit 92 a, discharges the refrigerant to the intermediate refrigerant pipe 15, and discharges the refrigerant discharged to the intermediate refrigerant pipe 15. Then, the refrigerant is sucked into the high-stage compression section 92b and further compressed, and then discharged to the discharge pipe 12.

  Here, the intermediate refrigerant pipe 15 is a refrigerant pipe for causing the high-stage compression section 92b to suck the refrigerant compressed and discharged by the low-stage compression section 92a. The discharge pipe 12 is a refrigerant pipe for sending the refrigerant discharged from the compression mechanism 92 to the switching mechanism 93. The discharge pipe 12 is provided with an oil separation mechanism 30 and a check mechanism 32.

  The oil separation mechanism 30 is a mechanism that separates refrigeration oil accompanying the refrigerant discharged from the compression mechanism 92 from the refrigerant and returns it to the suction side of the compression mechanism 92. The oil separation mechanism 30 mainly sucks refrigerating machine oil that is connected to the oil separator 31a and separated from the refrigerant, and that separates the refrigerating machine oil accompanying the refrigerant discharged from the compression mechanism 92 from the refrigerant. And an oil return pipe 31b that returns to the pipe 11. The oil return pipe 31b is provided with a pressure reducing mechanism 31c for reducing the pressure of the refrigerating machine oil. A capillary tube is used as the decompression mechanism 31c of the present embodiment. The check mechanism 32 is a mechanism for allowing the refrigerant flow from the discharge side of the compression mechanism 92 to the switching mechanism 93 and blocking the refrigerant flow from the switching mechanism 93 to the discharge side of the compression mechanism 92. In this embodiment, a check valve is used.

  As described above, the compression mechanism 92 includes the two compression elements 92a and 92b, and the refrigerant compressed by the low-stage compression unit 92a on the front stage of the compression elements 92a and 92b is the high stage on the rear stage side. The compressing unit 92b is further compressed.

  The compression mechanism 92 is not limited to a single uniaxial two-stage compression structure compression mechanism as in the present embodiment, and is a multistage compression type rather than a two-stage compression type such as a three-stage compression type. A multi-stage compression mechanism may be configured by connecting in series a plurality of compressors incorporating a single compression element and / or a plurality of compressors incorporating a plurality of compression elements. Further, it may be a parallel multi-stage compression type compression mechanism in which two or more multi-stage compression type compressors are connected in parallel.

(2-2) Switching mechanism The switching mechanism 93 is a mechanism for switching the flow direction of the refrigerant in the refrigerant circuit 10. The switching mechanism 93 is a four-way switching valve connected to the suction side of the compression mechanism 92, the discharge side of the compression mechanism 92, the second heat exchanger 60, and the use side heat exchanger 96. During the cooling operation, the switching mechanism 93 connects the discharge side of the compression mechanism 92 and the second heat exchanger 60, and connects the suction side of the compression mechanism 92 and the use side heat exchanger 96 (switching in FIG. 1). (See solid line for mechanism 93). On the other hand, during the heating operation, the switching mechanism 93 connects the discharge side of the compression mechanism 92 and the use side heat exchanger 96, and connects the suction side of the compression mechanism 92 and the second heat exchanger 60 (FIG. 1). (Refer to the broken line of the switching mechanism 93).

  As described above, the switching mechanism 93 is configured to be capable of switching between the cooling operation and the heating operation by switching the flow of the refrigerant compressed by the compression mechanism 92 (the high-stage compression unit 92b).

  Note that the switching mechanism 93 is not limited to the four-way switching valve, and is configured to have a function of switching the flow direction of the refrigerant as described above, for example, by combining a plurality of electromagnetic valves. There may be.

(2-3) Heat Exchange Unit FIG. 2 is a schematic diagram of the heat exchange unit 94. In FIG. 2, the flow direction of the refrigerant when the first heat exchanger 40 functions as a cooler and the second heat exchanger 60 functions as a radiator is indicated by arrows.

  The heat exchange unit 94 has a plurality of heat exchangers (in the present embodiment, the first heat exchanger 40 and the second heat exchanger 60). The heat exchanging unit 94 is supplied with water or air (air in the present embodiment) as a cooling source or a heating source for exchanging heat with the refrigerant flowing inside.

  The first heat exchanger 40 is provided in the intermediate refrigerant pipe 15. The first heat exchanger 40 has one end connected to the low-stage compression unit 92a and the other end connected to the high-stage compression unit 92b. The second heat exchanger 60 has one end connected to the switching mechanism 93 and the other end connected to the expansion mechanism 95.

  During the cooling operation, the first heat exchanger 40 functions as an intercooler that cools the refrigerant being compressed (intermediate pressure refrigerant), and the second heat exchanger 60 functions as a gas cooler that cools the high-pressure refrigerant. Specifically, during the cooling operation, the first heat exchanger 40 is an intermediate pressure refrigerant cooler in a refrigeration cycle that is compressed by the low-stage compression unit 92a on the front stage side and sucked into the high-stage compression unit 92b on the rear stage side. Function as. Moreover, the 2nd heat exchanger 60 functions as a heat radiator of the refrigerant | coolant compressed with the compression mechanism 92 (specifically the low stage compression part 92a and the high stage compression part 92b) at the time of air_conditionaing | cooling operation.

  Further, during the heating operation, the first heat exchanger 40 and the second heat exchanger 60 function as a low-pressure refrigerant evaporator. Specifically, during the heating operation, the first heat exchanger 40 and the second heat exchanger 60 are compressed by the compression mechanism 92 (the low-stage compression unit 92a and the high-stage compression unit 92b), and the use side heat exchanger 96 is compressed. It functions as an evaporator for the refrigerant that has dissipated heat. That is, during the heating operation, the first heat exchanger 40 does not function as a cooler for the intermediate pressure refrigerant compressed by the low-stage compression unit 92a, and the refrigerant decompressed by the expansion mechanism 95 together with the second heat exchanger 60. It functions as an evaporator.

  By the way, as shown in FIG. 1, the 2nd heat exchanger 60 and the switching mechanism 93 are connected by the 1st refrigerant pipe 13, and the 2nd heat exchanger 60 and the expansion mechanism 95 are the 2nd refrigerant pipe. 14 is connected. In addition to the first heat exchanger 40, the intermediate refrigerant pipe 15 is provided with a first electromagnetic valve 99, a second check mechanism 97, and a third electromagnetic valve 98. The first solenoid valve 99 and the third solenoid valve 98 are controlled to open and close only during the cooling operation so that the first heat exchanger 40 functions as a cooler for the intermediate pressure refrigerant compressed by the low-stage compression unit 92a. It is a valve that is called. The second check mechanism 97 allows the refrigerant to flow from the first heat exchanger 40 side to the high-stage compression unit 92b side, and the refrigerant from the high-stage compression unit 92b side to the first heat exchanger 40 side. In this embodiment, a check valve is used.

  The intermediate refrigerant tube 15 includes a first intermediate refrigerant tube 15a, a second intermediate refrigerant tube 15b, and a third intermediate refrigerant tube 15c. The first intermediate refrigerant pipe 15a is a refrigerant pipe connecting the discharge side of the low-stage compression unit 92a of the compression mechanism 92 and one end of the first heat exchanger 40 (the refrigerant inlet side during the cooling operation). is there. The first intermediate refrigerant pipe 15a is provided with a first electromagnetic valve 99. The second intermediate refrigerant pipe 15 b is a refrigerant pipe that connects the other end of the first heat exchanger 40 and the suction side of the high-stage compression unit 92 b of the compression mechanism 92. The second intermediate refrigerant pipe 15b is provided with a second check mechanism 97. The third intermediate refrigerant pipe 15c is a refrigerant pipe connecting the first intermediate refrigerant pipe 15a and the second intermediate refrigerant pipe 15b so as to bypass the first heat exchanger 40. A third solenoid valve 98 is provided in the third intermediate refrigerant pipe 15c.

  Furthermore, a first return pipe 16 and a second return pipe 17 are connected to the intermediate refrigerant pipe 15. The first return pipe 16 connects the second refrigerant pipe 14 and a portion of the second intermediate refrigerant pipe 15b between the second check mechanism 97 and the first heat exchanger 40. The first return pipe 16 is provided with a first return valve 19 capable of opening / closing control. The first return pipe 16 allows a part of the refrigerant flowing from the use side heat exchanger 96 to the second heat exchanger 60 through the expansion mechanism 95 to flow to the first heat exchanger 40 during the heating operation. Possible refrigerant pipe. The second return pipe 17 connects the suction pipe 11 and a portion of the first intermediate refrigerant pipe 15 a between the first heat exchanger 40 and the first electromagnetic valve 99. The second return pipe 17 is provided with a second return valve 18 capable of opening / closing control. The second return pipe 17 is a refrigerant pipe that can return the refrigerant that has undergone heat exchange in the first heat exchanger 40 to the suction pipe 11 during the heating operation.

(2-4) Expansion mechanism The expansion mechanism 95 is a mechanism that depressurizes the refrigerant, and an electric expansion valve is used in this embodiment. The expansion mechanism 95 has one end connected to the second heat exchanger 60 and the other end connected to the use side heat exchanger 96. The expansion mechanism 95 decompresses the high-pressure refrigerant radiated in the second heat exchanger 60 during the cooling operation before sending it to the use-side heat exchanger 96, and radiates heat in the use-side heat exchanger 96 during the heating operation. The high pressure refrigerant is decompressed before being sent to the first heat exchanger 40 and the second heat exchanger 60.

(2-5) Use-side heat exchanger The use-side heat exchanger 96 is a heat exchanger that functions as a refrigerant evaporator or a radiator. The use side heat exchanger 96 has one end connected to the expansion mechanism 95 and the other end connected to the switching mechanism 93. The use side heat exchanger 96 is supplied with water or air as a heating source or a cooling source for exchanging heat with the refrigerant flowing through the use side heat exchanger 96.

(3) Configuration of Heat Exchange Unit The heat exchange unit 94 has a two-stage structure in which the second heat exchanger 60 is stacked and fixed above the first heat exchanger 40. Below, the detailed structure of the 1st heat exchanger 40 and the 2nd heat exchanger 60 is demonstrated.

(3-1) First Heat Exchanger FIG. 3 is a schematic configuration diagram of the first heat exchanger 40. FIG. 4 is a top view of the first heat exchanger 40. FIG. 5 is a partial cross-sectional view around the first right header 43. FIG. 6 is a partial cross-sectional view around the first left header 42. In FIG. 3, the first corrugated fins 45 are omitted. Moreover, in FIG.3, FIG5 and FIG.6, the flow direction of the refrigerant | coolant of the 1st heat exchanger 40 at the time of air_conditionaing | cooling operation is shown by the arrow.

  The first heat exchanger 40 is a so-called micro-channel two-row heat exchanger, and includes two first heat exchange parts 41, two first right headers 43, and two first left headers 42. ing.

(3-1-1) First Heat Exchanger The first heat exchanger 41 includes a plurality of first flat tubes 44 and first corrugated fins 45 disposed between the first flat tubes 44. A plurality of paths in which the refrigerant branches and flows are formed. The first flat tube 44 is a plate member made of a plate-like metal (for example, aluminum or aluminum alloy) extending in a direction perpendicular to the longitudinal direction of the first left header 42 and the first right header 43. And the some 1st flat tube 44 is arrange | positioned along with the up-down direction so that each may have predetermined spacing. The first flat tube 44 is formed with a plurality of refrigerant flow passage holes 44a for circulating the refrigerant so as to penetrate in the longitudinal direction.

  The first corrugated fins 45 are heat transfer fins made of metal having a corrugated shape (for example, aluminum or aluminum alloy). The first corrugated fins 45 are disposed between the first flat tubes 44 and are bent into a corrugated shape so that a mountain portion and a valley portion are formed along the longitudinal direction of the first flat tube 44. It is configured. Note that the contact portion between the first flat tube 44 and the first corrugated fin 45 is joined by brazing or the like.

(3-1-2) The first right header and the first left header The first right header 43 and the first left header 42 are common to the plurality of paths of the first heat exchange unit 41 and are separated from each other, And each is arrange | positioned so that it may extend in a perpendicular direction. The first right header 43 and the first left header 42 have base members 46 a and 46 b and a connecting portion 47.

  The base members 46a, 46b are members made of metal (specifically, aluminum, aluminum alloy, etc.), and as shown in FIGS. 5 and 6, cylindrical portions 46aa, 46ba, fixed portions 46ab, 46bb, Have The cylindrical portions 46aa and 46ba are cylindrical portions and extend along the longitudinal direction of the first right header 43 and the first left header 42. The cylindrical portions 46aa and 46ba are formed therein with refrigerant channels 48a and 48b for circulating the refrigerant. The refrigerant channels 48a and 48b extend along the longitudinal direction of the cylindrical portions 46aa and 46ba. The fixing portions 46ab and 46bb are substantially rectangular portions that are integrally connected to the side walls of the cylindrical portions 46aa and 46ba. The fixed portions 46ab, 46bb are provided with a plurality of communication holes 48aa, 48ba communicating with the refrigerant flow hole 44a of the first flat tube 44, and the plurality of refrigerant flow holes 44a of the first flat tube 44 and the cylindrical portion. The refrigerant flow paths 48a and 48b of 46aa and 46ba communicate with each other through communication holes 48aa and 48ba.

  The connecting portion 47 includes a spacer member 47a, a fixing member 47b, and a holding member 47c. The spacer member 47a is disposed so as to be in contact with the fixing portions 46ab and 46bb. The fixing member 47b is disposed so as to contact the surface of the spacer member 47a on the first flat tube 44 side. The holding member 47c is disposed so as to surround the fixing portions 46ab and 46bb, the spacer member 47a, and the fixing member 47b from the side far from the cylindrical portions 46aa and 46ba.

  Further, the refrigerant flows into the first heat exchanger 40 or flows out of the first heat exchanger 40 into the upper part of the first right header 43 and the lower part of the first left header 42. Openings 49a and 49b for connecting pipes (specifically, the first intermediate refrigerant pipe 15a and the second intermediate refrigerant pipe 15b) are formed. Details of the openings 49a and 49b will be described later. Further, the first right header 43 and the first left header 42 and the pipe are connected via a pipe joint 80 described later.

(3-1-3) Flow of Refrigerant in First Heat Exchanger During the cooling operation, the refrigerant flows from the first right header 43 to the first left header 42 as shown in FIG. More specifically, the intermediate pressure refrigerant discharged from the low-stage compression portion 92 a on the front end side of the compression mechanism 92 flows into the refrigerant flow path 48 a of the first right header 43 through the opening 49 a of the first right header 43. . The refrigerant flowing into the refrigerant flow path 48 a of the first right header 43 is divided into the plurality of first flat tubes 44 and further distributed to the plurality of refrigerant flow channel holes 44 a formed in the first flat tubes 44. Then, it flows to the refrigerant flow path 48b formed in the first left header 42. At this time, the intermediate pressure refrigerant is radiated and cooled by exchanging heat with the passing air A passing outside. Then, the refrigerant that has flowed into the refrigerant flow path 48b of the first left header 42 flows through the opening 49b formed in the first left header 42 to the high-stage compression portion 92b on the rear stage side.

  Further, during the heating operation, the refrigerant flows from the first left header 42 to the first right header 43. More specifically, the low-pressure two-phase refrigerant flowing from the expansion mechanism 95 through the first return pipe 16 flows into the refrigerant flow path 48b of the first left header 42 through the opening 49b of the first left header 42. To do. The refrigerant flowing into the refrigerant flow path 48b of the first left header 42 is divided into a plurality of first flat tubes 44 and further distributed to a plurality of refrigerant flow passage holes 44a formed in each first flat tube 44. Then, it flows to the refrigerant flow path 48 a formed in the first right header 43. At this time, the low-pressure two-phase refrigerant is heated and evaporated by exchanging heat with the passing air A passing outside. The refrigerant flowing into the refrigerant flow path 48 a of the first right header 43 flows to the suction side of the compression mechanism 92 through the opening 49 a formed in the first right header 43.

(3-2) Second Heat Exchanger FIG. 7 is a schematic configuration diagram of the second heat exchanger 60. FIG. 8 is a top view of the second heat exchanger 60. FIG. 9 is a partial cross-sectional view around the second left headers 62a and 62b. FIG. 10 is a partial cross-sectional view around the return header 63. FIG. 11 is a diagram for explaining the arrangement of the components of the return header 63. In FIG. 7, the second corrugated fins 65a and 65b are omitted. Moreover, in FIG.7 and FIG.10, the flow direction of the refrigerant | coolant of the 2nd heat exchanger 60 at the time of air_conditionaing | cooling operation is shown by the arrow.

  The second heat exchanger 60 is a so-called microchannel heat exchanger, and includes a second heat exchange unit 61, two second left headers 62 a and 62 b, and a return header 63.

(3-2-1) Second Heat Exchange Unit The second heat exchange unit 61 includes a plurality of second flat tubes 64a and 64b and second corrugated fins 65a disposed between the second flat tubes 64a and 64b. , 65b.

  The second flat tubes 64a and 64b are tube members made of a plate-like metal (for example, aluminum or aluminum alloy) extending in a direction perpendicular to the longitudinal direction of the second left headers 62a and 62b. The plurality of second flat tubes 64a and 64b are arranged side by side in the up-down direction so that each has a predetermined interval. The second flat tubes 64a and 64b are formed with a plurality of coolant channel holes 64aa and 64ba for circulating the coolant so as to penetrate in the longitudinal direction.

  The second corrugated fins 65a and 65b are heat transfer fins made of metal having a corrugated shape (for example, aluminum or aluminum alloy). The second corrugated fins 65a and 65b are disposed between the second flat tubes 64a and 64b, and a crest portion and a trough portion are formed along the longitudinal direction of the second flat tubes 64a and 64b. It is configured to be bent into a waveform. Note that the contact portions between the second flat tubes 64a and 64b and the second corrugated fins 65a and 65b are joined by brazing or the like.

(3-2-2) Second Left Header The second left headers 62a and 62b are arranged so as to extend in the vertical direction. The second left headers 62a and 62b have base members 66a and 66b and a connecting portion 67a.

  The base members 66a and 66b are members made of metal (specifically, aluminum, aluminum alloy or the like), and include cylindrical portions 66aa and 66ba and fixed portions 66ab and 66bb. The cylindrical portions 66aa and 66ba are cylindrical portions and extend along the longitudinal direction of the second left headers 62a and 62b. The cylindrical portions 66aa and 66ba are formed therein with refrigerant flow paths 68a and 68b for circulating the refrigerant. The refrigerant flow paths 68a and 68b extend along the longitudinal direction of the cylindrical portions 66aa and 66ba. The fixing portions 66ab and 66bb are substantially rectangular portions that are integrally connected to the side walls of the cylindrical portions 66aa and 66ba (see FIG. 9). The fixed portions 66ab and 66bb are provided with a plurality of communication holes 68aa and 68ba communicating with the refrigerant flow holes 64aa and 64ba of the second flat tubes 64a and 64b, and a plurality of refrigerant flows of the second flat tubes 64a and 64b. The passage holes 64aa and 64ba and the refrigerant passages 68a and 68b of the cylindrical portions 66aa and 66ba communicate with each other through the communication holes 68aa and 68ba.

  The connecting portion 67a includes a spacer member 67aa, a fixing member 67ab, and a holding member 67ac (see FIG. 9). The spacer member 67aa is disposed so as to contact the fixing portions 66ab and 66bb. The fixing member 67ab is disposed so as to contact the surface of the spacer member 67aa on the second flat tube 64a, 64b side. The holding member 67ac is disposed so as to surround the fixing portions 66ab and 66bb, the spacer member 67aa, and the fixing member 67ab from the side far from the cylindrical portions 66aa and 66ba.

  Further, the refrigerant flows into the second heat exchanger 60 or flows out of the second heat exchanger 60 to the upper part of the second left header 62a and the lower part of the second left header 62b. Openings 69a and 69b for connecting pipes (specifically, the first refrigerant pipe 13 and the second refrigerant pipe 14) are formed. Details of the openings 69a and 69b will be described later. Further, the second left headers 62a and 62b and the pipe are connected via a pipe joint 80 described later.

(3-2-3) Return Header The return header 63 includes a holding member 63a, a fixing member 63b, a spacer member 63c, and a back plate 63d.

  As shown in FIG. 10, the holding member 63 a is a plate-like member in which the ends of the second flat tubes 64 a and 64 b are bonded and the horizontal cross-sectional shape is substantially U-shaped. As shown in FIG. 11, the holding member 63 a is provided with a plurality of flat tube insertion holes 63 aa in a plurality of stages in the vertical direction and in two rows in the horizontal direction. The flat tube insertion hole 63aa is a space into which the ends of the second flat tubes 64a and 64b are inserted.

  As shown in FIG. 10, the fixing member 63b is a plate-like member that is disposed so as to contact the surface of the spacer member 63c on the second flat tube 64a, 64b side. As shown in FIG. 11, the fixing member 63b is provided with a plurality of flat tube fastening holes 63ba in a plurality of steps in the vertical direction and in two rows in the horizontal direction. The flat tube fastening hole 63ba fixes the ends of the second flat tubes 64a and 64b together with the flat tube insertion hole 63aa.

  As shown in FIG. 10, the spacer member 63c is a plate-like member disposed between the fixing member 63b and the back plate 63d. As shown in FIG. 11, the spacer member 63c is provided with a plurality of spacer holes 63ca in a plurality of stages in the vertical direction. Each spacer hole 63ca forms a refrigerant junction 69 together with the fixing member 63b and the back plate 63d. The end surfaces of the second flat tubes 64a and 64b are in contact with the end surface of the spacer member 63c.

  The back plate 63d is a plate-like member disposed so as to face the end surfaces of the second flat tubes 64a and 64b. The back plate 63d is disposed in close contact with the holding member 63a and the spacer member 63c.

  As described above, the return header 63 in which the holding member 63a, the fixing member 63b, the spacer member 63c, and the back plate 63d are combined has two flat tube insertion holes 63aa, two flat tube retaining holes 63ba, and one spacer hole 63ca. Are formed in each step. Moreover, the edge part of 2nd flat tube 64a, 64b is inserted by flat tube insertion hole 63aa and flat tube fastening hole 63ba. The refrigerant flow passage hole 64aa of the second flat tube 64a and the refrigerant flow passage hole 64ba of the second flat tube 64b communicate with each other through the refrigerant junction portion 69.

(3-2-4) Flow of Refrigerant in Second Heat Exchanger During cooling operation, as shown in FIG. 7, the refrigerant flows from the second left header 62a to the second left header 62b via the return header 63. Flowing. More specifically, the high-pressure refrigerant discharged from the compression mechanism 92 flows into the refrigerant flow path 68a of the second left header 62a through the opening 69a of the second left header 62a. The refrigerant flowing into the refrigerant flow path 68a of the second left header 62a is divided into the plurality of second flat tubes 64a and further distributed to the plurality of refrigerant flow passage holes 64aa formed in the respective second flat tubes 64a. As a result, the refrigerant flows to the refrigerant junction 69 in the return header 63. Then, the refrigerant merged at the refrigerant merge portion 69 in the return header 63 is divided into a plurality of refrigerant flow holes 64ba formed in the respective second flat tubes 64b, and the refrigerant flow path 68b of the second left header 62b. It flows to. Thereafter, the refrigerant flowing into the refrigerant flow path 68b of the second left header 62b flows to the expansion mechanism 95 via the opening 69b formed in the second left header 62b. The high-pressure refrigerant is radiated and cooled by exchanging heat with the passing air A passing outside in the process of flowing through the second flat tubes 64a and 64b.

  Further, during the heating operation, the refrigerant flows from the second left header 62b to the second left header 62a via the return header 63. More specifically, the low-pressure two-phase refrigerant flowing from the expansion mechanism 95 flows into the refrigerant flow path 68b of the second left header 62b through the opening 69b of the second left header 62b. The refrigerant flowing into the refrigerant flow path 68b of the second left header 62b is divided into a plurality of second flat tubes 64b and further distributed to a plurality of refrigerant flow passage holes 64ba formed in the respective second flat tubes 64b. Then, the refrigerant flows to the refrigerant junction 69 in the return header 63. Then, the refrigerant merged at the refrigerant merge portion 69 in the return header 63 is divided into a plurality of refrigerant flow hole 64aa formed in each second flat tube 64a, and the refrigerant flow path 68a of the second left header 62a. It flows to. Thereafter, the refrigerant flowing into the refrigerant flow path 68a of the second left header 62a flows to the suction side of the compression mechanism 92 through the opening 69a formed in the second left header 62a. The low-pressure two-phase refrigerant is heated and evaporated by exchanging heat with the passing air A passing outside in the process of flowing through the second flat tubes 64a and 64b.

(3-3) Openings of Each Header FIG. 12 is a partial cross-sectional view of the lower part of the first left header 42 cut along the longitudinal direction.

  As described above, pipes (first intermediate refrigerant pipe 15a, second intermediate refrigerant pipe 15b, first refrigerant pipe 13 and second refrigerant pipe 14) are connected to the headers 42, 43, 62a and 62b, respectively. Openings 49a, 49b, 69a, and 69b are formed. In each header 42, 43, 62a, 62b, the positions where the openings 49a, 49b, 69a, 69b are formed are different, but the portions where the openings 49a, 49b, 69a, 69b are formed. The mode (hereinafter referred to as an opening) is the same. Moreover, in this embodiment, the component parts (a base member and a connection part) of each header 42, 43, 62a, 62b are made the same, and are shared.

  Therefore, in the following, the opening 49b formed in the first left header 42 will be described as an example.

  As shown in FIG. 12, the opening 149 in which the opening 49b of the first left header 42 is formed has a recess 149a that is recessed toward the inner surface 42a side of the first left header 42, that is, toward the refrigerant flow path 48b. Including. The opening 49b is formed in the bottom surface (butting surface) 149b of the recess 149a. In addition, it is designed so that the inner diameter of the standing portion 149c standing from the bottom surface 149b of the recess 149a matches the outer diameter of the connecting portion 83 of the pipe joint 80 described later.

(4) Piping Joint FIG. 13 is a cross-sectional view around the lower part of the first left header 42 of the first heat exchanger 40 cut along the longitudinal direction (vertical direction). FIG. 14 is a cross-sectional view around the lower part of the first left header 42 of the first heat exchanger 40 cut along a direction perpendicular to the longitudinal direction (horizontal direction). FIG. 15 is a side view of a section around the lower portion of the first left header 42 of the first heat exchanger 40 cut along the longitudinal direction (vertical direction).

  The pipe joint 80 allows the refrigerant to flow into the first heat exchanger 40 and the second heat exchanger 60 and the first heat exchanger 40 and the second heat exchanger 60, or the first heat exchanger 40 and the second heat exchanger 60. 2 For connecting a pipe for allowing the refrigerant to flow out of the heat exchanger 60. Specifically, in the first heat exchanger 40, the pipe joint 80 connects the first right header 43 and the first intermediate refrigerant pipe 15a, and the first left header 42 and the second intermediate refrigerant pipe 15b. And connected. In the second heat exchanger 60, the pipe joint 80 connects the second left header 62a and the first refrigerant pipe 13, and connects the second left header 62b and the second refrigerant pipe 14. Yes.

  In the present embodiment, the pipe joints 80 that connect the headers 42, 43, 62a, 62b and the refrigerant pipes 13, 14, 15a, 15b all have the same configuration. The pipe joint 80 connected to the first left header 42 will be described.

  The pipe joint 80 is a substantially cylindrical member (see FIG. 2), and a refrigerant flow path 81 through which a refrigerant flows is formed. The pipe joint 80 includes a main body portion 82 including a portion connected to the second intermediate refrigerant pipe 15b, and a connection portion 83 that is integrally connected to the main body portion 82 and connected to the first left header 42. Have. More specifically, as shown in FIG. 15, the connection portion 83 is a portion that is positioned so as to fit in the recess 149 a of the first left header 42 in a state where the pipe joint 80 and the first left header 42 are connected. The main body portion 82 is a portion protruding from the virtual outer surface F of the opening 149 (the virtual extension surface of the outer surface 42b of the first left header 42) F. Then, in a state where the pipe joint 80 and the first left header 42 are connected, the outer peripheral surface 83a of the connecting portion 83 abuts on the inner peripheral surface 149e of the standing portion 149c of the concave portion 149a, and at the tip portion of the connecting portion 83 An end surface 85a of a certain tip end portion 85 is configured to abut against a bottom surface 149b of the recess 149a.

  And the front-end | tip part 85 of the connection part 83 is formed in the taper shape which the opening area of the inner surface 85b expands gradually. For this reason, the inner diameter of the refrigerant flow path 81 of the pipe joint 80 is large at the tip end portion 85. In addition, the front-end | tip part 85 here means the part in which the inner surface 85b is formed in the taper shape (refer FIG. 15). In the present embodiment, in a state where the pipe joint 80 and the first left header 42 are connected, the connection portion 83 is located on the inner side (the inner surface 42a side of the first left header 42) than the virtual outer surface F of the opening 149. Therefore, the distal end portion 85 that is the distal end portion of the connection portion 83 is naturally positioned on the inner side of the virtual outer surface F of the opening 149. Furthermore, in this embodiment, the tapered leading edge 86 that is the opening edge of the leading end portion 85 is designed to coincide with the opening edge 149d of the opening 49b formed in the bottom surface 149b.

(5) Operation of Air Conditioner FIG. 16 is a refrigerant pressure-enthalpy diagram illustrating a refrigeration cycle during cooling operation. FIG. 17 is a refrigerant temperature-entropy diagram illustrating the refrigeration cycle during the cooling operation. FIG. 18 is a refrigerant pressure-enthalpy diagram illustrating a refrigeration cycle during heating operation. FIG. 19 is a refrigerant temperature-entropy diagram illustrating a refrigeration cycle during heating operation.

  Hereinafter, the operation of the air conditioner 90 will be described with reference to FIGS. 1 and 16 to 19. In the following description, “high pressure” means high pressure in the refrigeration cycle (that is, pressure at points d and e in FIGS. 16 and 17 and pressure at points d and f in FIGS. 18 and 19). , “Low pressure” means low pressure in the refrigeration cycle (that is, pressure at points a and f in FIGS. 16 and 17, pressure at points a and e in FIGS. 18 and 19), and “intermediate pressure” means The intermediate pressure in the refrigeration cycle (that is, the pressure at points b, c, and c ′ in FIGS. 16 to 19) is meant.

(5-1) Cooling Operation During the cooling operation, the switching mechanism 93 is controlled to the state indicated by the solid line in FIG. 1 and the opening degree of the expansion mechanism 95 is adjusted. Further, the first electromagnetic valve 99 is controlled to be in an open state. Further, the third electromagnetic valve 98, the first return valve 19 and the second return valve 18 are controlled to be closed.

  When the compression mechanism 92 is driven in the state of the refrigerant circuit 10, the low-pressure refrigerant (see point a in FIGS. 1, 16, and 17) is sucked into the compression mechanism 92 from the suction pipe 11. After being compressed to an intermediate pressure by the low-stage compression section 92a, it is discharged to the intermediate refrigerant pipe 15 (specifically, the first intermediate refrigerant pipe 15a) (see point b in FIGS. 1, 16, and 17). ).

  The intermediate-pressure refrigerant discharged from the low-stage compressor 92a flows through the first intermediate refrigerant pipe 15a and is sent to the first heat exchanger 40. The intermediate-pressure refrigerant sent to the first heat exchanger 40 is radiated and cooled by exchanging heat with air as a cooling source that passes outside in the first heat exchanger 40 (FIG. 1). (See point c in FIGS. 16 and 17). The intermediate pressure refrigerant cooled in the first heat exchanger 40 flows through the second intermediate refrigerant pipe 15b, is sucked into the high-stage compression section 92b, and is further compressed. Then, the high-pressure refrigerant compressed by the high-stage compression unit 92b is discharged from the compression mechanism 92 to the discharge pipe 12 (see point d in FIGS. 1, 16, and 17).

  Here, the high-pressure refrigerant discharged from the compression mechanism 92 is compressed to a pressure exceeding the critical pressure (that is, the critical pressure Pcp at the critical point CP shown in FIG. 16) by the two-stage compression operation by the compression elements 92a and 92b. ing. The high-pressure refrigerant discharged from the compression mechanism 92 flows into the oil separator 31a, and the accompanying refrigeration oil is separated. The refrigerating machine oil separated from the high-pressure refrigerant in the oil separator 31a flows into the oil return pipe 31b and is reduced in pressure by the pressure reduction mechanism 31c provided in the oil return pipe 31b, and then is supplied to the suction pipe 11 of the compression mechanism 92. It is returned and sucked into the compression mechanism 92 again.

  The high-pressure refrigerant discharged from the compression mechanism 92 is sent to the second heat exchanger 60 through the oil separator 31a, the check mechanism 32, and the switching mechanism 93. The high-pressure refrigerant sent to the second heat exchanger 60 performs heat exchange with the air as a cooling source that passes outside in the second heat exchanger 60 to be dissipated and cooled (FIG. 1, (See point e in FIGS. 16 and 17).

  The high-pressure refrigerant cooled by the second heat exchanger 60 is reduced in pressure by the expansion mechanism 95 to become a low-pressure two-phase refrigerant, and is sent to the use-side heat exchanger 96 (see FIGS. 1, 16, and 17). See point f). The low-pressure two-phase refrigerant sent to the use-side heat exchanger 96 is heated by exchanging heat with water or air as a heating source to evaporate (FIGS. 1, 16, and 17). See point a). The low-pressure refrigerant evaporated in the use side heat exchanger 96 is again sucked into the compression mechanism 92 via the switching mechanism 93 and the suction pipe 11. Thus, in the air conditioner 90, the cooling operation is performed.

(5-2) Heating Operation During the heating operation, the switching mechanism 93 is controlled to the state shown by the broken line in FIG. 1 and the opening degree of the expansion mechanism 95 is adjusted. Further, the third electromagnetic valve 98, the first return valve 19 and the second return valve 18 are controlled to be in the open state. Further, the first electromagnetic valve 99 is controlled to be closed.

  When the compression mechanism 92 is driven in the state of the refrigerant circuit 10, the low-pressure refrigerant (see point a in FIGS. 1, 18, and 19) is sucked into the compression mechanism 92 from the suction pipe 11. After being compressed to an intermediate pressure by the low-stage compression section 92a, it is discharged to the intermediate refrigerant pipe 15 (specifically, the first intermediate refrigerant pipe 15a) (see point b in FIGS. 1, 18 and 19). ). The intermediate-pressure refrigerant discharged from the low-stage compressor 92a flows to the third intermediate refrigerant pipe 15c in the middle of the first intermediate refrigerant pipe 15a, and flows from the third intermediate refrigerant pipe 15c to the second intermediate refrigerant pipe 15b ( 1 (see point c ′ in FIGS. 1, 18 and 19), it is sucked into the high-stage compression section 92b and further compressed. Then, the high-pressure refrigerant compressed by the high-stage compression unit 92b is discharged from the compression mechanism 92 to the discharge pipe 12 (see point d in FIGS. 1, 18 and 19).

  Here, the high-pressure refrigerant discharged from the compression mechanism 92 is subjected to the critical pressure (that is, the critical pressure Pcp at the critical point CP shown in FIG. 18) by the two-stage compression operation by the compression elements 92a and 92b as in the cooling operation. ) Compressed to a pressure exceeding The high-pressure refrigerant discharged from the compression mechanism 92 flows into the oil separator 31a and the accompanying refrigeration oil is separated, as in the cooling operation. The refrigerating machine oil separated from the high-pressure refrigerant in the oil separator 31a flows into the oil return pipe 31b and is reduced in pressure by the pressure reduction mechanism 31c provided in the oil return pipe 31b, and then is supplied to the suction pipe 11 of the compression mechanism 92. It is returned and sucked into the compression mechanism 92 again.

  The high-pressure refrigerant discharged from the compression mechanism 92 is sent to the use side heat exchanger 96 through the oil separator 31a, the check mechanism 32, and the switching mechanism 93. The high-pressure refrigerant sent to the use-side heat exchanger 96 is cooled by being dissipated by heat exchange with water or air as a cooling source in the use-side heat exchanger 96 (FIGS. 1, 18, and FIG. (See point f on 19). The high-pressure refrigerant radiated and cooled by the use-side heat exchanger 96 is sent to the expansion mechanism 95, where it is depressurized by the expansion mechanism 95 to become a low-pressure two-phase refrigerant (FIGS. 1, 18, and 19). See point e).

  The low-pressure two-phase refrigerant decompressed by the expansion mechanism 95 is sent to the second heat exchanger 60 and flows through the first return pipe 16 to the first heat exchanger 40. The low-pressure two-phase refrigerant sent to the second heat exchanger 60 is heated and exchanges heat with air as a heating source (see point a in FIGS. 1, 18 and 19). . On the other hand, the low-pressure two-phase refrigerant sent to the first heat exchanger 40 is also heated and exchanges heat with air as a heating source (see point a in FIGS. 1, 18 and 19). reference). The low-pressure refrigerant evaporated in the second heat exchanger 60 flows through the suction pipe 11 via the switching mechanism 93 and is sucked into the compression mechanism 92 again. The low-pressure refrigerant evaporated in the first heat exchanger 40 is again sucked into the compression mechanism 92 via the first intermediate refrigerant pipe 15a, the second return pipe 17 and the suction pipe 11. Thus, in the air conditioner 90, the heating operation is performed.

(6) Effects (6-1) Comparative Example FIG. 20 is a view for explaining a pipe joint 980 according to a comparative example.

  As shown in FIG. 20, the pipe joint 980 according to the comparative example has an inner surface of the tip portion of the connection portion 983 of the pipe joint 980 that is not formed in a tapered shape, and the inner diameter of the refrigerant flow path 981 of the pipe joint 980 is The main body portion 982 and the connection portion 983 are constant without change.

(6-2) Comparative Analysis FIG. 21 is a diagram showing the ratio of the pressure loss occupied by the pipe joint to the pressure loss of the entire first heat exchanger connected using the pipe joints 80 and 980 according to the present invention and the comparative example. It is. FIG. 21 shows a result when the pipe joints 80 and 980 are employed in the first left header 42 of the first heat exchanger 40.

  When the ratio of the pressure loss occupied by the pipe joints 80 and 980 to the pressure loss of the entire first heat exchanger 40 using the pipe joints 80 and 980 according to the present invention and the comparative example is analyzed, the result is as shown in FIG. . In the case of the pipe joint 980 according to the comparative example, for example, when the refrigerant flow rate is 300 kg / h, the pressure loss occupied by the pipe joint 980 with respect to the pressure loss of the entire first heat exchanger 40 is about 40%. On the other hand, when the pipe joint 80 according to the present invention is used, when the refrigerant flow rate is 300 kg / h, the pressure loss occupied by the pipe joint 80 with respect to the pressure loss of the entire first heat exchanger 40 is about 20%. It is.

  In the case of the pipe joint 980 according to the comparative example, when the refrigerant flows from the first left header 42 into the pipe joint 980, the connection portion 983 can easily form a vortex of the refrigerant. On the other hand, in the case of the pipe joint 80 according to the present invention, when the refrigerant flows into the pipe joint 80 from the first left header 42, the refrigerant flows along the inner surface 85b of the tip portion 85 formed in a tapered shape. The connection part 83 makes it difficult for the refrigerant to vortex. For this reason, when the pipe joint 980 which concerns on a comparative example is used, it is thought that the pressure loss in the connection part of a header and piping becomes large rather than the pipe joint 80 which concerns on this invention is used. Therefore, when the pipe joint 80 according to the present invention is employed, the pressure loss can be reduced as compared with the case where the pipe joint 980 according to the comparative example is employed. As a result, the first heat exchange is performed. The performance degradation of the container 40 can be suppressed.

(7) Features (7-1)
There exists a problem that the performance of a heat exchanger falls because the pressure loss of the refrigerant | coolant in the heat exchanger used as a cooler which cools the intermediate pressure refrigerant | coolant between a low stage compression part and a back | latter stage compression part becomes large. In particular, when a microchannel heat exchanger having a small hole diameter in the refrigerant flow path is used as a cooler that cools the intermediate pressure refrigerant, performance degradation due to pressure loss becomes a problem.

  Therefore, in the present embodiment, in the first heat exchanger 40 that functions as a cooler that cools the intermediate pressure refrigerant, the tip of the connection portion of the first intermediate refrigerant pipe 15a with the first right header 43, and the second The distal end portion of the connection portion of the intermediate refrigerant pipe 15b with the first left header 42, that is, the distal end portion 85 of the connection portion 83 of the pipe joint 80 is formed in a tapered shape in which the opening area of the inner surface 85b gradually increases. Yes. For this reason, the inner diameter (hole diameter) of the refrigerant flow path 81 of the pipe joint 80 can be increased at the connection portion between the first right header 43 and the first left header 42. Accordingly, the pressure loss of the refrigerant at the connection portion between the first intermediate refrigerant pipe 15a and the second intermediate refrigerant pipe 15b and the first right header 43 and the first left header 42 can be reduced.

  Thereby, the performance fall of the 1st heat exchanger 40 which functions as a cooler can be reduced.

  Further, as a means for reducing the pressure loss of the refrigerant in the connection portion between the pipe and the first heat exchanger 40, it is conceivable to increase the pipe diameter of the pipe connected to each header of the first heat exchanger 40. However, when trying to increase the pipe diameter, the number of parts at the connection between the pipe and the header increases.

  On the other hand, by adopting the pipe joint 80 of the present invention, it is possible to reduce the pressure loss of the refrigerant at the connection portion between the pipe and each header without adding additional components.

(7-2)
In the present embodiment, the opening 149 of the first left header 42 includes a recess 149a, and the opening 49b is formed in the bottom surface 149b of the recess 149a. And the end face 85a of the front-end | tip part 85 which is the front-end | tip part of the connection part 83 is configured to abut against the bottom face 149b of the recess 149a in a state where the pipe joint 80 and the first left header 42 are connected.

  Thereby, when connecting the piping joint 80 and the 1st left side header 42, positioning of the piping joint 80 can be made easy.

(7-3)
In the present embodiment, in a state where the pipe joint 80 and the first left header 42 are connected, the distal end portion 85 of the pipe joint 80 is located inside the virtual outer surface F of the opening 149. Thereby, compared with the case where the front-end | tip part (part formed in the taper shape) of a pipe joint is located in the outer side of the virtual outer surface of an opening part, the fall of the pressure strength of the 1st left side header 42 is reduced. Is able to.

(7-4)
In the present embodiment, the tapered tip edge 86 of the tip portion 85 is designed to coincide with the opening edge 149d of the opening 49b formed in the bottom surface 149b. Thereby, compared with the case where a taper front end edge is located inside the opening edge of a header, it becomes difficult to become resistance of the flow of a refrigerant.

(7-5)
In the present embodiment, when the first heat exchanger 40 functions as a cooler, the refrigerant flows from the first left header 42 side toward the second intermediate refrigerant pipe 15b side. For this reason, the refrigerant flows through the pipe joint 80 connecting the first left header 42 and the second intermediate refrigerant pipe 15b from the first left header 42 side toward the pipe joint 80 side. Therefore, it is possible to reduce the pressure loss of the refrigerant on the refrigerant outlet side of the first heat exchanger 40, that is, on the outlet side of the first left header 42 where the refrigerant flowing through the first heat exchange unit 41 gathers. is made of.

  By the way, when the microchannel heat exchanger is employed as a cooler for cooling the intermediate pressure refrigerant, the ratio of the pressure loss in the pipe joint on the outlet side of the heat exchanger is large with respect to the pressure loss of the entire heat exchanger. In the present embodiment, since the pressure loss in the pipe joint 80 on the outlet side of the first heat exchanger 40 is reduced, the pressure loss in the first heat exchanger 40 can be greatly reduced.

(7-6)
In the present embodiment, the first heat exchanger 40 can function not only as a cooler but also as an evaporator.

(8) Modification (8-1) Modification A
In the above embodiment, the taper tip edge 86 of the pipe joint 80 and the opening edge 149d of the first left header 42 are designed to coincide with each other. However, as shown in FIG. May be configured to be located outside the opening edge 149d of the first left header 42. Even if the tapered leading edge 86 is configured to be located outside the opening edge 149d, it is less likely to cause resistance to the flow of the refrigerant as compared to the case where the tapered leading edge is located inside the opening edge of the header. Become.

(8-2) Modification B
In the said embodiment, all the pipe joints 80 which connect each header 42, 43, 62a, 62b and each refrigerant | coolant pipe | tube 13, 14, 15a, 15b are the same structures, The 1st heat exchanger 40 and 2nd heat | fever The pressure loss at the inlet side and the outlet side of the refrigerant in the exchanger 60 is reduced.

  However, it is not necessary to employ the pipe joint 80 according to the present invention on all of the refrigerant inlet side and outlet side of the first heat exchanger 40 and the second heat exchanger 60, and at least the pipe joint 80 according to the present invention. May be used on the refrigerant inlet side or outlet side of the first heat exchanger 40. When the microchannel heat exchanger is adopted as a cooler that cools the intermediate pressure refrigerant, the ratio of the pressure loss in the pipe joint on the outlet side of the heat exchanger to the pressure loss of the entire heat exchanger is large. Therefore, the pipe joint 80 is preferably used on the outlet side of the first heat exchanger 40.

(8-3) Modification C
In the said embodiment, although the 1st heat exchanger 40 functions as an evaporator at the time of heating operation, it is not limited to this, If the 1st heat exchanger 40 functions as a cooler which cools an intermediate pressure refrigerant | coolant. For example, the first heat exchanger 40 may not function as an evaporator.

  Since this invention can reduce the performance fall of the heat exchanger which functions as a cooler, application to the refrigerating device provided with the cooler is effective.

15b Second intermediate refrigerant pipe (pipe)
40 1st heat exchanger (heat exchanger)
41 1st heat exchange part (heat exchange part)
42 First left header (refrigerant header)
49b Opening 83 Connection part 85 Tip part 86 Taper tip edge 90 Air conditioner (refrigeration apparatus)
92 Compression mechanism 92a Low stage compression part 92b High stage compression part 149 Opening part 149b Bottom surface (butting surface)
149d opening edge

JP 2009-133581 A

Claims (6)

A compression mechanism (92) having a low-stage compression section (92a) and a high-stage compression section (92b) connected in series with the low-stage compression section;
A heat exchange part (41) having a plurality of paths through which the refrigerant flows and a refrigerant header (42) common to the plurality of paths, between the low-stage compression part and the high-stage compression part; A heat exchanger (40) functioning as a cooler for cooling the intermediate pressure refrigerant of
A pipe (15b) connected to the refrigerant header;
With
The tip end portion (85) of the connection portion (83) with the refrigerant header of the pipe is formed in a tapered shape in which the opening area of the inner surface gradually increases,
Refrigeration equipment (90). The refrigerant header has an opening (149) in which an opening (49b) for connecting the pipe is formed,
The opening includes an abutting surface (149b) against which the tip of the tip end abuts.
The refrigeration apparatus according to claim 1. The tip is located on the inner side of the virtual outer surface (F) of the opening,
The refrigeration apparatus according to claim 2. The taper tip edge (86) of the tip portion coincides with the opening edge (149d) formed on the abutting surface, or is located outside the opening edge,
The refrigeration apparatus according to any one of claims 1 to 3. The refrigerant flows from the refrigerant header side toward the piping side,
The refrigeration apparatus according to any one of claims 1 to 4. When the heat exchanger functions as an evaporator, a two-phase refrigerant flows from the pipe side toward the refrigerant header side.
The refrigeration apparatus according to any one of claims 1 to 5.

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