JP6111655B2 - Refrigeration equipment - Google Patents

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 during the cooling operation, the heat source side heat exchanger is provided. Functions as a gas cooler, and the intercooler cools the intermediate pressure refrigerant that is 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. Acts 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 pressure loss of the refrigerant in the heat exchanger (hereinafter referred to as sub heat exchanger) used as an intercooler that cools the intermediate pressure refrigerant between the low-stage compressor and the high-stage compressor is increased. There exists a problem that the performance of a heat exchanger falls.

  Then, the subject of this invention is providing the refrigeration apparatus which can reduce the performance fall of the sub heat exchanger which cools an intermediate pressure refrigerant | coolant.

  A refrigeration apparatus according to a first aspect of the present invention includes a compression mechanism, a sub heat exchanger, a pipe, and a main heat exchanger. The compression mechanism includes a low-stage compression unit and a high-stage compression unit. The high stage compression unit is connected in series with the low stage compression unit. A sub heat exchanger has a sub heat exchange part and a sub heat exchanger side header. The sub heat exchanger exchanges heat between the refrigerant flowing inside and the other heat medium. The sub heat exchanger side header is connected to the end of the sub heat exchange unit. Further, the sub heat exchanger can cool the intermediate pressure refrigerant between the low-stage compression section and the high-stage compression section. The pipe communicates with the internal space of the sub heat exchanger side header. Moreover, piping is for flowing the intermediate pressure refrigerant | coolant discharged from the low stage compression part to a sub heat exchanger. The main heat exchanger is disposed adjacent to the sub heat exchanger in the vertical direction. Moreover, the main heat exchanger has a main heat exchange part and a main heat exchanger side header. The main heat exchange unit performs heat exchange between the refrigerant flowing inside and the other heat medium. The main heat exchanger side header is connected to the end of the main heat exchange part. Further, the main heat exchanger can cool the refrigerant discharged from the high stage compression unit. Furthermore, the area of the sub heat exchanger side header is larger than the area of the main heat exchanger side header in plan view. In addition, in the plan view, the sub heat exchanger side header and the main heat exchanger side header partially overlap. And piping is the upper surface or lower surface which opposes the main heat exchanger side header among the surfaces which a sub heat exchanger side header contains, and is connected to the part which has not overlapped with the main heat exchanger side header.

  In the refrigeration apparatus according to the first aspect of the present invention, piping for flowing the intermediate pressure refrigerant to the sub heat exchanger is connected to the upper surface or the lower surface of the sub heat exchanger side header. For this reason, if the internal space of the sub heat exchanger side header extends in the vertical direction, the sub heat exchange from the pipe is less than when the pipe is connected to the side surface of the sub heat exchanger side header. The pressure loss of the refrigerant flowing toward the container header can be reduced.

  Thereby, the performance degradation of the sub heat exchanger can be reduced.

  In the refrigeration apparatus according to the second aspect of the present invention, in the refrigeration apparatus according to the first aspect, the outer edge of the main heat exchanger side header is located inside the outer edge of the sub heat exchanger side header in plan view. For this reason, in this refrigeration apparatus, it can be comprised so that the connection part of piping and the sub heat exchanger side header may not interfere with the main heat exchanger side header.

  In the refrigeration apparatus according to the third aspect of the present invention, in the refrigeration apparatus according to the first aspect or the second aspect, the internal space of the sub heat exchanger side header is configured to extend along the vertical direction. For this reason, in this refrigeration apparatus, the direction in which the connecting portion of the pipe with the sub heat exchanger side header extends can be the same as the direction in which the internal space of the sub heat exchanger side header extends.

  Thereby, the pressure loss of the refrigerant | coolant which flows toward the sub heat exchanger side header from piping can be reduced.

  The refrigerating apparatus according to the fourth aspect of the present invention is the refrigerating apparatus according to any one of the first to third aspects, wherein the pipe is connected to the sub heat exchanger side header by a pipe joint. Moreover, it is comprised so that the internal diameter of a sub heat exchanger side header and the internal diameter of a piping joint may become equal. For this reason, compared with the case where the internal diameter of a piping joint is smaller than the internal diameter of a sub heat exchanger side header, the pressure loss of the refrigerant | coolant in the connection part of piping and a sub heat exchanger side header can be reduced.

  A refrigeration apparatus according to a fifth aspect of the present invention is the refrigeration apparatus according to any one of the first to fourth aspects, wherein the sub heat exchange unit has a flat multi-hole tube in which a plurality of flow path holes are formed.

  Here, when a heat exchanger having a refrigerant passage with a small hole diameter such as a flat multi-hole pipe is used as an intercooler, performance degradation due to refrigerant pressure loss becomes a particular problem.

  In the refrigeration apparatus according to the fifth aspect of the present invention, the sub heat exchange unit has a flat multi-hole tube, but the pipe is connected to the upper surface or the lower surface of the sub heat exchanger side header, so The pressure loss of the refrigerant flowing toward the heat exchanger side header can be reduced. Thereby, the performance fall of a sub heat exchanger can be reduced.

  In the refrigeration apparatus according to the first aspect of the present invention, it is possible to reduce the performance degradation of the sub heat exchanger.

  The refrigeration apparatus according to the second aspect of the present invention can be configured such that the connection portion between the pipe and the sub heat exchanger side header does not interfere with the main heat exchanger side header.

  In the refrigeration apparatus according to the third aspect of the present invention, the pressure loss of the refrigerant flowing from the piping toward the sub heat exchanger side header can be reduced.

  In the refrigeration apparatus according to the fourth aspect of the present invention, the pressure loss of the refrigerant at the connection portion between the pipe and the sub heat exchanger side header can be reduced.

  In the refrigeration apparatus according to the fifth aspect of the present invention, it is possible to reduce the performance degradation of the sub heat exchanger.

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 figure which looked at the 1st right side header and return header of a heat exchange unit from the upper part. The figure which looked at the section of the 1st left-hand header and piping joint from the side. The figure which looked at the section of the 1st right header and piping joint 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 schematic diagram of the heat exchange unit which concerns on a comparative example. The figure for demonstrating the 1st heat exchanger which concerns on a comparative example. The figure which shows the ratio of the pressure loss which a piping joint accounts with respect to the pressure loss of the whole 1st heat exchanger which concerns on this invention and a comparative example.

  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 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).

  Thus, the switching mechanism 93 is configured to be able to switch between the cooling operation and the heating operation by switching the flow of the refrigerant compressed by the compression mechanism 92.

  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 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 includes a first heat exchanger 40 and a second heat exchanger 60, as shown in FIG. 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. The heat exchange is performed between the refrigerant flowing in the interior and another heat medium (air in the present embodiment).

  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) First right header and first left header The first right header 43 and the first left header 42 are arranged so as to be separated from each other and extend in the vertical direction (up and down direction). And connected to the end of the first flat tube 44. 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. Specifically, the opening 49 a is formed on the end surface of the cylindrical portion 46 aa that is the upper surface of the first right header 43. The opening 49b is formed on the outer peripheral surface of the cylindrical portion 46ba corresponding to the side surface of the first left header 42. The first right header 43 and the first intermediate refrigerant pipe 15a are connected via a pipe joint 180 described later, and the first left header 42 and the second intermediate refrigerant pipe 15b are connected to a pipe joint 80 described later. Connected through. That is, the first intermediate refrigerant pipe 15a and the refrigerant flow path 48a of the first right header 43 are communicated with each other via the pipe joint 180, and the second intermediate refrigerant pipe 15b and the refrigerant flow path 48b of the first left header 42 are connected. And communicate with each other via a pipe joint 80.

(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 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, and performs heat exchange between the refrigerant flowing inside and another heat medium (air in this embodiment).

  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 header 62a, 62b is disposed so as to extend in the vertical direction (vertical direction), and is connected to one end of the second flat tubes 64a, 64b. ing. 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. Specifically, the opening 69a is formed on the outer peripheral surface of the cylindrical portion 66aa corresponding to the side surface of the second left header 62a. The opening 69b is formed on the outer peripheral surface of the cylindrical portion 66ba corresponding to the side surface of the second left header 62b. The second left header 62a and the first refrigerant pipe 13 are connected via a pipe joint 80 described later, and the second left header 62b and the second refrigerant pipe 14 are connected via a pipe joint 80 described later. Connected.

(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.

  In the present embodiment, a surface corresponding to the lower surface of the return header 63 (specifically, a surface constituted by an end surface of the back plate 63d, an end surface of the spacer member 63c, an end surface of the fixing member 63b, and an end surface of the holding member 63a). ) Is a surface corresponding to the upper surface of the first right headers 43, 43 (specifically, end surfaces of the base members 46a, 46a, end surfaces of the spacer members 47a, 47a, end surfaces of the fixing members 47b, 47b, and holding members). 47c and 47c are designed to be smaller than the area). More specifically, the area of the surface constituted by the end face of the back plate 63d of the return header 63, the end face of the spacer member 63c, the end face of the fixing member 63b, and the end face of the holding member 63a, and the base members of the first right headers 43 and 43 The end surfaces of the fixed portions 46ab and 46ab, the end surfaces of the spacer members 47a and 47a, the end surfaces of the fixing members 47b and 47b, and the surface area constituted by the end surfaces of the holding members 47c and 47c of 46a and 46a are made equal. Designed to. That is, in the present embodiment, the area of the upper surface of the first right headers 43 and 43 is larger than the area of the lower surface of the return header 63 by the area of the end surfaces of the cylindrical portions 46aa and 46aa.

(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) Arrangement of First Heat Exchanger and Second Heat Exchanger FIG. 12 is a diagram for explaining a state where the first right headers 43 and 43 and the return header 63 overlap.

  The first heat exchanger 40 and the second heat exchanger 60 are disposed adjacent to each other in the vertical direction. In the present embodiment, 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, as shown in FIG. .

  In the present embodiment, the first flat tubes 44 and the first corrugated fins 45 included in the first heat exchange unit 41 of the first heat exchanger 40 and the second heat exchange unit 61 of the second heat exchanger 60 are included. The second flat tubes 64a and 64b and the second corrugated fins 65a and 65b are made common and common. Moreover, in this embodiment, the component (base member 46a, 46b and the connection part 47) which comprises the 1st right header 43 and the 1st left header 42 of the 1st heat exchanger 40, and the 2nd heat exchanger 60 The components (the base members 66a and 66b and the connecting portion 67a) constituting the second left headers 62a and 62b are the same and shared. In the present embodiment, the area of the surface corresponding to the lower surface of the return header 63 is designed to be smaller than the area of the surface corresponding to the upper surfaces of the first right headers 43 and 43. For this reason, when the heat exchange unit 94 is viewed in a plan view, the return header 63 and the first right header 43 are arranged so as to partially overlap each other, and the outer edge of the return header 63 is the outer edge of the first right header 43. (See FIG. 12). The outer edge of the return header 63 referred to here is the outer edge of the back plate 63d in plan view, and the outer edge of the first right header 43 is the outer peripheral edge of the cylindrical portion 46aa in plan view. is there. In the present embodiment, the second heat exchanger 60 is disposed above the first heat exchanger 40, and the lower end surface of the holding member 63 a of the return header 63 and the first right headers 43 and 43. The holding members 47c and 47c overlap so as to face the upper end surfaces.

(4) Piping joint FIG. 13 is a side view of the periphery of the first left header 42 of the first heat exchanger 40 cut along the longitudinal direction (vertical direction). FIG. 14 is a side view of the periphery of the first right header 43 of the first heat exchanger 40 cut along the longitudinal direction (vertical direction). In FIG. 14, the flow direction of the refrigerant during the cooling operation is indicated by an arrow.

  The pipe joints 80 and 180 are used for allowing 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 for the first heat exchanger 40. And a pipe for allowing the refrigerant to flow out of the second heat exchanger 60.

  Specifically, in the first heat exchanger 40, the first right header 43 and the first intermediate refrigerant pipe 15a are connected by a pipe joint 180, and the first left header 42 and the second intermediate refrigerant pipe 15b are connected. Are connected by a pipe joint 80. In the second heat exchanger 60, the second left header 62a and the first refrigerant pipe 13 are connected by a pipe joint 80, and the second left header 62b and the second refrigerant pipe 14 are connected by a pipe joint 80. It is connected. In the present embodiment, the pipe joints 80 that connect the headers 42, 62a, 62b and the refrigerant pipes 13, 14, 15b all have the same configuration, and as an example, are connected to the first left header 42. The piping joint 80 to be performed 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. Then, one end of the pipe joint 80 is connected to the second intermediate refrigerant pipe 15b so that the second intermediate refrigerant pipe 15b, the refrigerant flow path 81 of the pipe joint 80, and the refrigerant flow path 48b of the first left header 42 communicate with each other. The other end is connected to the first left header 42. As shown in FIG. 13, the end of the pipe joint 80 on the side connected to the first left header 42 is connected so as to extend in the horizontal direction from the side surface of the first left header 42. . Therefore, in a state where the pipe joint 80 and the first left header 42 are connected, the refrigerant flow path 81 of the pipe joint 80 intersects the direction in which the refrigerant flow path 48b of the first left header 42 extends (this embodiment). Then, it can be said that it extends in the orthogonal direction).

  Although FIG. 13 shows an example in which the end of the pipe joint 80 is fitted and connected to the opening 49b formed on the side surface of the first left header 42, the pipe joint 80 and the first left header are illustrated. The connection means with 42 is not limited to this.

  The pipe joint 180 that connects the first right header 43 and the first intermediate refrigerant pipe 15a is a substantially cylindrical member (see FIG. 2) having a substantially L-shaped cross section, and the refrigerant in which the refrigerant flows. A flow path 181 is formed. In the present embodiment, the inner diameter of the pipe joint 180 (specifically, the hole diameter of the refrigerant flow path 181) and the inner diameter of the first right header 43 (specifically, the hole diameter of the refrigerant flow path 48a) Are designed to be equal. Also, one end of the pipe joint 180 is connected to the first intermediate refrigerant pipe 15a so that the first intermediate refrigerant pipe 15a, the refrigerant flow path 181 of the pipe joint 180, and the refrigerant flow path 48a of the first right header 43 communicate with each other. The other end is connected to the first right header 43. As shown in FIG. 2, the end of the pipe joint 180 on the side connected to the first right header 43 is the upper surface of the first right header 43 and overlaps the lower surface of the return header 63. It connects so that it may extend upward (vertical direction) from the part which is not. Therefore, in a state where the pipe joint 180 and the first right header 43 are connected, the refrigerant flow path 48a of the first right header 43 is provided in the vicinity of the first right header 43 in the refrigerant flow path 181 of the pipe joint 180. It can be said that it is extended in the same direction as the direction of (see FIG. 14).

  14 shows an example in which the end of the pipe joint 180 is fitted and connected to the opening 49a formed in the end face of the cylindrical portion 46aa of the first right header 43. The connection means with the first right header 43 is not limited to this. FIG. 14 shows a pipe joint 180 in which the outer diameter of the pipe joint 180 is smaller than the outer diameter of the first right header 43. The outer diameter of the pipe joint 180 and the outer diameter of the first right header 43 are illustrated. May be designed to be equal to each other. In particular, when the inner diameter of the pipe joint 180 and the inner diameter of the first right header 43 are equal, the outer diameter of the pipe joint 180 and the outer diameter of the first right header 43 are preferably designed to be equal. .

(5) Operation of Air Conditioner FIG. 15 is a refrigerant pressure-enthalpy diagram illustrating a refrigeration cycle during cooling operation. FIG. 16 is a refrigerant temperature-entropy diagram illustrating the refrigeration cycle during the cooling operation. FIG. 17 is a refrigerant pressure-enthalpy diagram illustrating a refrigeration cycle during heating operation. FIG. 18 is a refrigerant temperature-entropy diagram illustrating a refrigeration cycle during heating operation.

  Hereinafter, operation | movement of the air conditioner 90 is demonstrated using FIG. 1, FIG. 15-FIG. In the following description, “high pressure” means high pressure in the refrigeration cycle (that is, pressure at points d and e in FIGS. 15 and 16 and pressure at points d and f in FIGS. 17 and 18). , “Low pressure” means low pressure in the refrigeration cycle (that is, pressure at points a and f in FIGS. 15 and 16 and pressure at points a and e in FIGS. 17 and 18), and “intermediate pressure” means Mean an intermediate pressure in the refrigeration cycle (that is, pressure at points b, c, and c ′ in FIGS. 15 to 18).

(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, 15, and 16) 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, 15 and 16). ).

  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. 15 and 16). 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, 15, and 16).

  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. 15) 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. 15 and 16).

  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, 15, and 16). 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, 15, and 16). 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, 17, and 18) is sucked into the compression mechanism 92 from the suction pipe 11, and first, the front side 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, 17, and 18). ). 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, 17 and 18), 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, 17, and 18).

  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. 17) 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 in the use-side heat exchanger 96 through heat exchange with water or air as a cooling source (FIGS. 1, 17, and FIG. (See point f on 18). 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, 17, and 18). 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, 17 and 18). . 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, 17 and 18). 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. 19 is a schematic diagram of a heat exchange unit 94 ′ including a first heat exchanger 40 ′ according to a comparative example. FIG. 20 is a diagram showing a state in which the pipe joint 80 is connected to the first right header 43, which is a part of the first heat exchanger 40 ′ according to the comparative example. In FIG. 20, the flow direction of the refrigerant during the cooling operation is indicated by an arrow.

  In 1st heat exchanger 40 'which concerns on a comparative example, in order to make a refrigerant flow in into 1st heat exchanger 40', or piping for flowing out a refrigerant from 1st heat exchanger 40 '(specifically, The first intermediate refrigerant pipe 15a) is connected to the side surface of the first right header 43 (see FIG. 19). Specifically, as shown in FIG. 20, the end of the pipe joint 80 on the side connected to the first right header 43 is from the outer peripheral surface of the cylindrical portion 46 aa that is the side of the first right header 43. They are connected so as to extend in the horizontal direction. The configuration of the pipe joint 80 is the same as the pipe joint 80 connecting the headers 42, 62a, 62b and the refrigerant pipes 13, 14, 15b in the present embodiment.

(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 40, 40 ′ according to the present invention and the comparative example.

  FIG. 21 shows an analysis of the ratio of the pressure loss occupied by the pipe joint to the pressure loss of the entire first heat exchanger 40, 40 'according to the present invention and the comparative example. In the case of the pipe joint 80 according to the comparative example, for example, 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 18%. On the other hand, when the pipe joint 180 according to the present invention is used, when the refrigerant flow rate is 300 kg / h, the pressure loss occupied by the pipe joint 180 with respect to the pressure loss of the entire first heat exchanger 40 is about 8%. It is.

  In the case of the first heat exchanger 40 ′ according to the comparative example, the direction in which the refrigerant flow path 81 of the pipe joint 80 extends and the direction in which the refrigerant flow path 48a of the first right header 43 extends are orthogonal to each other. Compared with the case where the extending direction of the refrigerant flow path 181 of the pipe joint 180 and the extending direction of the refrigerant flow path 48a of the first right header 43 are the same as in the first heat exchanger 40 according to the first heat exchanger 40, 1 It is considered that the pressure loss when the refrigerant flows into the right header 43 increases.

  Further, when the pipe joint 80 is connected to the side surface of the first right header 43 as in the first heat exchanger 40 ′ according to the comparative example, the outer diameter of the pipe joint 80 is structurally set to the first right header 43. Must be smaller than the outer diameter (specifically, the outer diameter of the cylindrical portion 46aa). Further, considering the strength of the connecting portion between the first right header 43 and the pipe joint 80, the outer diameter of the pipe joint 80 is set to the inner diameter of the first right header 43 (specifically, the hole diameter of the refrigerant flow path 48a). It is preferable to make it smaller. Then, the inner diameter of the pipe joint 80 (specifically, the hole diameter of the refrigerant flow path 81) becomes smaller than the inner diameter of the first right header 43. On the other hand, in the first heat exchanger 40 according to the present invention, since the pipe joint 180 is connected to the upper surface of the first right header 43, the outer diameter of the pipe joint 180 is changed to the outer diameter of the first right header 43. The inner diameter of the pipe joint 180 (specifically, the hole diameter of the refrigerant flow path 181) can be made equal to the inner diameter of the first right header 43. Therefore, the first heat exchanger 40 according to the present invention has a pressure loss at the connection portion between the first intermediate refrigerant pipe 15a and the first right header 43, as compared with the first heat exchanger 40 ′ according to the comparative example. Can be reduced.

  Thus, since the 1st heat exchanger 40 concerning the present invention can reduce pressure loss compared with 1st heat exchanger 40 'concerning a comparative example, the performance of the 1st heat exchanger 40 The decrease can be suppressed.

(7) Features (7-1)
In the present embodiment, in plan view, the area of the surface corresponding to the upper surface of the first right header 43 is larger than the area of the surface corresponding to the lower surface of the return header 63 and a part thereof is overlapped. ing. The pipe joint 180 is connected to a portion of the upper surface of the first right header 43 that does not face the lower surface of the return header 63. Thus, the refrigerant flow path 181 of the pipe joint 180 and the refrigerant flow path 48a of the first right header 43 can be coaxial, so that the pipe joint 180 is directed to the first right header 43. The pressure loss of the flowing intermediate pressure refrigerant can be reduced.

  Thereby, the performance fall of the 1st heat exchanger 40 can be reduced.

(7-2)
In the present embodiment, the outer edge of the return header 63 is located inside the outer edge of the first right header 43 in plan view. For this reason, even if the extending direction of the refrigerant flow path 181 of the pipe joint 180 and the extending direction of the refrigerant flow path 48a of the first right header 43 are the same direction, the pipe joint 180 and the return header 63 do not interfere with each other. Can be like that.

(7-3)
In the present embodiment, the refrigerant flow path 48 a of the first right header 43 is configured to extend along the vertical direction (vertical direction) of the first right header 43. For this reason, the direction in which the refrigerant flow path 48a of the first right header 43 extends and the direction in which the vicinity of the first right header 43 extends in the refrigerant flow path 181 of the pipe joint 180 can be made the same direction. Thereby, the pressure loss of the intermediate pressure refrigerant flowing from the pipe joint 180 toward the first right header 43 can be reduced.

(7-4)
In the present embodiment, the inner diameter of the pipe joint 180 is designed to be equal to the inner diameter of the first right header 43. Thereby, the pressure loss in the connection part of the 1st intermediate refrigerant pipe 15a and the 1st right side header 43 can be reduced.

(7-5)
When a so-called microchannel heat exchanger having a refrigerant channel with a small hole diameter such as a flat multi-hole tube is employed as a cooler for cooling the intermediate pressure refrigerant, a performance degradation due to refrigerant pressure loss becomes a problem. In the present embodiment, the first heat exchanger 40 is a heat exchanger having a first flat tube 44 in which a plurality of refrigerant passage holes 44 a having a small hole diameter are formed, but the pipe joint 180 is connected to the first right header 43. Therefore, the pressure loss of the intermediate pressure refrigerant flowing from the pipe joint 180 toward the first right header 43 can be reduced. As a result, the performance deterioration of the first heat exchanger 40 can be reduced. Have been able to.

(8) Modification (8-1) Modification A
In the above embodiment, the second heat exchanger 60 is stacked above the first heat exchanger 40, and the pipe joint 180 is connected to the upper surface of the first right header 43. Instead of this, when the first heat exchanger 40 is stacked above the second heat exchanger 60, piping is provided on a portion of the lower surface of the first right header 43 that does not overlap with the upper surface of the return header 63. A joint 180 may be connected.

(8-2) Modification B
In the above embodiment, the inner diameter of the pipe joint 180 is designed to be equal to the inner diameter of the first right header 43, but the present invention is not limited to this, and the inner diameter of the pipe joint 180 is larger than the inner diameter of the first right header 43. May be small. However, in order to reduce the pressure loss at the connection portion between the pipe and the first right header 43, the difference between the inner diameter of the pipe joint 180 and the inner diameter of the first right header 43 is preferably small.

(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 sub heat exchanger which cools an intermediate pressure refrigerant, application to a refrigerating device provided with a sub heat exchanger is effective.

15a First intermediate refrigerant pipe (pipe)
40 1st heat exchanger (sub heat exchanger)
41 1st heat exchange part (sub heat exchange part)
43 1st right header (sub heat exchanger side header)
44 1st flat tube (flat multi-hole tube)
44a Refrigerant flow path hole (flow path hole)
48a Refrigerant flow path (internal space)
60 Second heat exchanger (main heat exchanger)
61 2nd heat exchange part (main heat exchange part)
63 Return header (Main heat exchanger side header)
90 Air conditioner (refrigeration equipment)
92 Compression mechanism 92a Low stage compression section 92b High stage compression section 180 Piping joint

JP 2009-133581 A

Claims (4)

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 sub heat exchange section (41) for exchanging heat between the refrigerant flowing inside and another heat medium; and a sub heat exchanger side header (43) connected to an end of the sub heat exchange section. And a sub heat exchanger (40) capable of cooling the intermediate pressure refrigerant between the low-stage compression section and the high-stage compression section,
A pipe (15a) that communicates with the internal space (48a) of the sub heat exchanger side header, and allows the intermediate pressure refrigerant discharged from the low-stage compression section to flow to the sub heat exchanger;
A main heat exchanging part (61) arranged adjacent to the sub heat exchanger in the vertical direction and exchanging heat between the refrigerant flowing inside and the other heat medium, and an end of the main heat exchanging part A main heat exchanger (60) having a main heat exchanger side header (63) connected to the section, and capable of cooling the refrigerant discharged from the high-stage compression section,
With
In plan view, the area of the sub heat exchanger side header is larger than the area of the main heat exchanger side header, and the sub heat exchanger side header and the main heat exchanger side header partially overlap. The outer edge of the main heat exchanger side header is located inside the outer edge of the sub heat exchanger side header,
The pipe is connected to a portion of the surface included in the sub heat exchanger side header that is an upper surface or a lower surface that faces the main heat exchanger side header and does not overlap the main heat exchanger side header. ,
Refrigeration equipment (90). The internal space of the sub heat exchanger side header is configured to extend along the vertical direction.
The refrigeration apparatus according to claim 1 . The pipe is connected to the sub heat exchanger side header by a pipe joint (180),
The inner diameter of the sub heat exchanger side header and the inner diameter of the pipe joint are configured to be equal.
The refrigeration apparatus according to claim 1 or 2 . The sub heat exchange part has a flat multi-hole tube (44) in which a plurality of flow path holes (44a) are formed.
The refrigeration apparatus according to any one of claims 1 to 3 .

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