JP2007032949A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger of excellent heat exchange performance capable of relatively reducing an installation space. <P>SOLUTION: This heat exchanger is provided with a heat exchange part 10 comprising an outer tube 2, an inner tube 3, and a plurality of fins 4 formed integrally on an outer circumferential face of the inner tube 3 and extended along a longitudinal direction thereof. The heat exchange part 10 is bent at least in one portion. One part of the fins 4 is made to abut on inner circumferential faces of a bent inner portion 2a and a bent outer portion 2b of the outer tube 2, in a cross-sectional face of the bent portion 10A in the heat exchange part 10, and the inner tube 3 is clampedly fixed via the fins 4 by the bent inner portion 2a and the bent outer portion 2b of the outer tube 2. A fluid mixing part 20 with clearances formed respectively between the tip parts 4 of the fins 4 and the inner circumferential face of the outer tube 2 is provided in circumferential both sides of the portion where the one part of the fins 4 is made to abut on the inner circumferential faces of the bent inner portion 2a and the bent outer portion 2b of the outer tube 2, in the cross-sectional face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a heat exchanger, and more specifically, for example, an intermediate for exchanging heat between a refrigerant coming out of a compressor, a gas cooler, an evaporator, a gas-liquid separator, and a gas cooler and a refrigerant coming out of the evaporator and passed through the gas-liquid separator. The present invention relates to a heat exchanger that includes a heat exchanger and is suitably used as an intermediate heat exchanger in a supercritical refrigeration cycle that uses a supercritical refrigerant such as CO ₂ .

  In this specification and claims, the term “aluminum” includes aluminum alloys in addition to pure aluminum.

  2. Description of the Related Art Conventionally, car air conditioners mounted on automobiles are widely used that are composed of a compressor, a condenser, an evaporator, a gas-liquid separator, and a decompressor, and a refrigeration cycle that uses a chlorofluorocarbon refrigerant.

However, in recent years, for the purpose of environmental protection, it is considered to mount a supercritical refrigeration cycle using a supercritical refrigerant such as CO _{2 in} a car as a car air conditioner.

  The supercritical refrigeration cycle consists of a compressor, a gas cooler, an evaporator, an accumulator as a gas-liquid separator, an expansion valve as a decompressor, and a low-temperature and low-pressure An intermediate heat exchanger that exchanges heat with the refrigerant is provided.

  By the way, the intermediate heat exchanger in the supercritical refrigeration cycle is a heat exchanger that was not found in the conventional refrigeration cycle using the chlorofluorocarbon refrigerant, and can efficiently store the intermediate heat exchanger in the engine room of the automobile. At present, it is considered to be disposed in a portion between the gas cooler and the evaporator in the engine room.

  As a heat exchanger used for the intermediate heat exchanger of the supercritical refrigeration cycle described above, a straight outer tube, a straight inner tube arranged concentrically at intervals in the outer tube, and an outer peripheral surface of the inner tube. It has a heat exchange part consisting of fins that are integrally formed to be spaced in the direction and extend in the length direction of the inner pipe, and connectors fixed to both ends of the inner and outer pipes of the heat exchange part. The gap between the outer tube and the inner tube of the heat exchange part serves as a first fluid passage and the inside of the inner tube serves as a second fluid passage. The first fluid of the heat exchange unit is connected to each connector. A first flow path that allows the passage to communicate with the outside, and a second flow path that is independent of the first flow path and communicates the second fluid path of the heat exchange section to the outside. What is in contact with the inner peripheral surface of the outer tube is known (see Patent Document 1).

  In the intermediate heat exchanger described in Patent Document 1, in order to obtain a desired heat exchange performance between the refrigerant flowing in the first fluid passage of the heat exchange section and the refrigerant flowing in the second fluid passage, both fluids are used. It is necessary to increase the heat transfer area between fluids flowing in the passage. However, in this case, the lengths of both the inner and outer pipes must be increased, and the inner and outer pipes are straight pipes, so there is a problem that the installation space for the intermediate heat exchanger becomes relatively large. In particular, when mounted on an automobile, the space for installation is limited in the engine room, so that the intermediate heat exchanger cannot be efficiently stored, and the feasibility is low.

  In addition, since the first fluid passage is divided into a plurality of passage portions by fins provided in the inner pipe, the refrigerant flowing through each passage portion is not efficiently mixed, and the refrigerant flowing through both fluid passages. There is a risk that the heat exchange efficiency between them will be insufficient.

Furthermore, although the tips of all the fins of the inner tube are in contact with the inner peripheral surface of the outer tube, the fins are not fixed to the outer tube, so in some cases, rattling between the fins and the outer tube may occur. May occur, and abnormal noise due to vibration may occur.
International Publication No. 03/085344 Pamphlet

  An object of the present invention is to provide a heat exchanger that can solve the above-mentioned problems and can reduce the installation space.

  In order to achieve the above object, the present invention comprises the following aspects.

  1) At the both ends of both the outer and inner tubes of the outer tube, the inner tube provided at intervals in the outer tube, and the heat exchange part composed of fins provided between the outer tube and the inner tube A heat exchanger having a fixed connector, wherein the gap between the outer tube and the inner tube of the heat exchange section serves as a first fluid passage and the inner tube serves as a second fluid passage. And the heat exchanger by which the heat exchange part is bent in at least one place.

  2) The heat exchanger according to 1) above, wherein the fins are integrally formed so as to be circumferentially spaced on the outer peripheral surface of the inner tube and to extend in the length direction of the inner tube.

  3) In the cross section of the bent part of the heat exchange part, the tips of some fins are in contact with the inner peripheral surface of the bent inner part and outer bent part of the outer pipe, and the bent inner part and bent part of the outer pipe The heat exchanger according to 2) above, wherein the inner tube is sandwiched and fixed by the outer portion via the fin.

  4) In the cross section of the bent part of the heat exchange part, the fins are respectively provided on both sides in the circumferential direction of the part where the tip part of the fin is in contact with the inner peripheral surface of the bent inner part and the bent outer part of the outer tube. 3. The heat exchanger according to 3) above, wherein a fluid mixing section in which a gap is formed is provided between the tip of the outer pipe and the inner peripheral surface of the outer tube.

  5) The heat exchanging portion has a plurality of bent portions, and the bent portion bent in one plane including the axes of both the inner and outer tubes, and the other one including the axes of both the inner and outer tubes and intersecting the plane. The heat exchanger according to any one of 1) to 4) above, wherein a bent portion bent in one plane is mixed.

  6) The heat exchanger according to any one of 1) to 5) above, wherein the outer tube, the inner tube, and the connector are each made of aluminum.

  7) A compressor, a gas cooler, an evaporator, a gas-liquid separator, a decompressor, and an intermediate heat exchanger for exchanging heat between the refrigerant coming out of the gas cooler and the refrigerant coming out of the evaporator, and a supercritical refrigerant A refrigeration cycle to be used, wherein the intermediate heat exchanger is a heat exchanger described in any one of 1) to 6) above.

  8) The above description 7), wherein the low-pressure refrigerant coming out of the evaporator flows in the first fluid passage of the intermediate heat exchanger, and the high-pressure refrigerant coming out of the gas cooler also flows in the second fluid passage. Refrigeration cycle.

  9) The refrigeration cycle according to 7) or 8) above, wherein the supercritical refrigerant is carbon dioxide.

10) A vehicle on which the refrigeration cycle according to any one of 7) to 9) above is mounted as a car air conditioner.
11) Compressor, outdoor heat exchanger, gas-liquid separator, decompressor, and heat exchanger for heating the coolant that exchanges heat between the high-temperature and high-pressure heat medium compressed by the compressor and the engine coolant sent from the engine to the heater core A heating cycle using a supercritical heat medium, wherein the coolant heating heat exchanger comprises the heat exchanger described in any one of 1) to 6) above.

  12) The above description 11), wherein the engine coolant flows in the first fluid passage of the heat exchanger for heating the coolant, and the high-temperature and high-pressure heat medium compressed by the compressor also flows in the second fluid passage. Heating cycle.

  13) The heating cycle according to 11) or 12) above, wherein the supercritical heat medium is carbon dioxide.

  14) A vehicle on which the heating cycle according to any one of the above 11) to 13) is mounted as a car air conditioner.

  According to the heat exchanger of 1) above, since the heat exchange part is bent at at least one place, the total heat transfer area between the fluids flowing in the first and second fluid passages of the heat exchange part is desired. Even if the size is necessary to obtain the heat exchange performance, the linear distance between the two connectors is shorter than that of the intermediate heat exchanger described in Patent Document 1. Therefore, the linear length of the installation space of this heat exchanger can be made smaller than that of the heat exchanger described in Patent Document 1. In addition, for example, when it is mounted on an automobile, it can be bent into an arbitrary shape according to the empty space of the automobile, and the space in the engine room of the automobile can be used effectively.

  According to the heat exchanger of 2), the heat transfer area between the fluids flowing in the first and second fluid passages is increased, and the heat exchange efficiency is improved. Further, since the fins are formed integrally with the inner tube, the number of parts is reduced.

  According to the heat exchanger of 3) above, the inner tube is fixed to the outer tube, and the generation of abnormal noise due to vibration can be prevented.

  According to the heat exchanger of the above 4), when a fluid is caused to flow through the first fluid passage, the fluid is mixed efficiently in the fluid mixing portion in combination with the inertial force when passing through the bent portion. Therefore, the heat exchange performance between the fluids flowing in both fluid passages is improved by the turbulent flow effect and the fluid temperature equalizing effect as compared with the intermediate heat exchanger described in Patent Document 1.

  When the heat exchanger of 5) above is mounted on a car, for example, it can be bent into any shape according to the free space of the car, and the space in the engine room of the car can be used effectively. The feasibility is high.

  Further, in the heat exchanger of the above 5), when the configuration of the above 3) is provided, the effect of preventing abnormal noise due to the inner tube being fixed to the outer tube is further improved.

  Further, in the heat exchanger of the above 5), in the case of having the configuration of the above 4), the heat exchanger includes a bent portion bent in one plane including the axes of both the inner and outer tubes, the axes of both the inner and outer tubes, and the above The position in the circumferential direction of both the inner and outer pipes of the fluid mixing portion is different from the bent portion that is bent in the other one plane that intersects the plane. Therefore, the fluid flowing in the first fluid passage is mixed more efficiently in each fluid mixing portion in combination with the inertial force when passing through each bending portion, and the turbulent effect and the uniform fluid temperature are obtained. The effect of improving the heat exchange performance between the fluids flowing in the two fluid passages due to the effect of the crystallization effect becomes remarkable.

  According to the heat exchanger of 6) above, the heat transfer efficiency between the fluid flowing through the first fluid passage and the fluid flowing through the second fluid passage is improved.

  Embodiments of the present invention will be described below with reference to the drawings.

In the following description, the upper and lower sides and the left and right sides in FIG.

  Moreover, the same code | symbol is attached | subjected to the same part and the same thing through all drawings, and the overlapping description is abbreviate | omitted.

  FIG. 1 shows the overall configuration of a first embodiment of a heat exchanger according to the present invention, and FIGS. FIG. 5 shows a supercritical refrigeration cycle using the heat exchanger of FIG. 1 as an intermediate heat exchanger.

  1 to 4, a heat exchanger (1) includes an outer tube (2) having a circular cross section and an inner tube (3) having a circular cross section inserted concentrically in the outer tube (2) at intervals. ) And the heat exchange part (10) composed of fins (4) provided on the outer peripheral surface of the inner pipe (3), and fixed to both ends of both pipes (2) and (3) of the heat exchange part (10) A heat exchanger (10), ie, both pipes (2) (3), at least one location, here including one axis of both pipes (2) (3). It is bent at two places in the plane (P). The bent part is indicated by (10A).

  The outer tube (2) is made of a metal, here an aluminum extruded profile. The inner pipe (3) is made of a metal, here, an aluminum extruded shape, and on the outer peripheral surface thereof, a plurality of fins (4) are spaced in the circumferential direction and extend in the length direction of the inner pipe (3). Are integrally formed. In the linear part (10B) of the heat exchange part (10) excluding the bent part (10A), there is a slight gap between the tip of the fin (4) and the inner peripheral surface of the outer pipe (2). (See FIG. 2). Both ends of the inner tube (3) protrude outward from the outer tube (2), and the fin (4) is cut out over the entire outer protruding portion (3a) to provide a finless portion (8). It has been. A plurality of inner fins (9) extending over the entire length are integrally formed on the inner peripheral surface of the inner pipe (3) at intervals in the circumferential direction (see FIGS. 2 and 3). The gap between the outer pipe (2) and the inner pipe (3) is the first fluid passage (6), and the inner pipe (3) is the second fluid passage (7). Yes.

  The heat exchange section (10) is formed by inserting a straight inner pipe (3) into a straight outer pipe (2) and then bending it. This bending process is performed either before or after fixing the connector (5) to both pipes (2) and (3). As shown in FIG. 3, in the bent portion (10A) of the heat exchange section (10), the outer tube (2) connects the bending center and the axis of the outer tube (2) on the plane (P). Slightly crushed in the direction. Then, in the cross section of the bent portion (10A) of the heat exchange section (10), that is, the cross section orthogonal to the plane (P) (corresponding to the cross section taken along the line BB in FIG. 1), The tip part of the fin (4) of the part is in contact with the inner peripheral surface of the bent inner part (2a) and the bent outer part (2b) of the outer pipe (2), and the bent inner part of the outer pipe (2) ( The inner tube (3) is clamped and fixed by the fin (4) by the bent outer portion (2b) and 2a). In addition, in the cross section of the bent portion (10A) of the heat exchange section (10), the tips of some fins (4) are connected to the bent inner portion (2a) and the bent outer portion (2b) of the outer tube (2). On both sides in the circumferential direction of the contacting part (upper and lower sides in FIG. 3), the gap between the tip of the fin (4) and the inner peripheral surface of the outer tube (2) is a linear part (10B). Is larger than between the tip of the fin (4) and the inner peripheral surface of the outer tube (2), and a fluid mixing portion (20) is formed here.

  As shown in FIG. 4, the connector (5) is made of a block made of metal, here aluminum, and has a horizontal columnar portion (5a) and a rectangular parallelepiped portion (5b) connected to the upper end of the columnar portion (5a). It becomes more. Hereinafter, the left connector (5) will be described. On the right end surface of the columnar part (5a) of the connector (5), an annular wall (11) is integrally formed so as to protrude rightward so that the end of the outer pipe (2) is fitted. A working recess (12) is formed. And the end of the outer tube (2) is fitted into the outer tube insertion recess (12) of the connector (5), the outer surface of the outer tube (2) and the tip of the annular wall (11), that is, The opening peripheral part of the recess (12) is joined. This joining is performed by brazing, here torch brazing.

  One end of the connector (5) opens to a portion surrounded by the annular wall (11) on the right end surface of the cylindrical portion (5a), and the other end opens to the upper surface of the rectangular parallelepiped portion (5b). A flow path (13) communicating with the fluid path (6) is formed. Also, a through-hole extending in the left-right direction between the left end surface of the lateral portion present in the cylindrical portion (5a) in the flow path (13) of the connector (5) and the left end surface (outer surface) of the cylindrical portion (5a) (14) is formed. The left portion of the finless portion (8) of the inner tube (3) is inserted into the through hole (14). The left end of the finless portion (8) protrudes outward from the opening on the left end face side of the cylindrical portion (5a) in the through hole (14), and the outer periphery of the finless portion (8) of the inner tube (3) The surface is joined to the peripheral edge of the left end opening of the through hole (14) in the cylindrical portion (5a). This joining is performed by brazing, here torch brazing.

  An annular wall (15) is integrally formed on the left end surface of the cylindrical portion (5a) of the connector (5) around the through hole (14) so as to protrude leftward. The left end of the finless portion (8) of the inner pipe (3) protrudes to the left of the annular wall (15), and the portion protruding from the annular wall (15) in the finless portion (8) and the annular wall A union screw (16) is arranged so as to cover (15). The annular wall (15) is fitted into the right end large diameter portion (17a) of the through hole (17) formed in the union screw (16), and the left end portion of the finless portion (8) is in the through hole (17). It is fitted into a small diameter portion (17b) that is continuous with the right end large diameter portion (17a). The right end portion of the union screw (16) is fitted in an annular recess (18) formed in a portion around the annular wall (15) on the left end surface of the cylindrical portion (5a), and the union screw (16) The right end of the outer peripheral surface of the cylindrical member and the inner peripheral surface of the recess (18) in the cylindrical portion (5a) are joined. This joining is performed by brazing, here torch brazing. The union screw (16) of one connector (5) is used to connect a pipe for supplying fluid into the second fluid passage (7), and the union screw (16) of the other connector (5). ) Is used to connect a pipe for discharging fluid from the second fluid passage (7).

  The connector (5) has a female screw hole (19) extending downward from the upper surface of the rectangular parallelepiped portion (5b). The female screw hole (19) of one connector (5) is used to connect a pipe for supplying fluid into the first fluid passage (6), and the female screw hole of the other connector (5). (19) is used to connect a piping pipe for discharging fluid from the first fluid passage (6).

  The right connector (5) has a configuration opposite to that of the left connector (5), and is fixed to the outer tube (2) and the inner tube (3) in the same manner as the left connector (5).

  FIG. 5 shows a supercritical refrigeration cycle using the heat exchanger (1) described above as an intermediate heat exchanger.

In FIG. 5, the supercritical refrigeration cycle uses CO ₂ as a supercritical refrigerant, and includes a compressor (21), a gas cooler (22), an evaporator (23), an accumulator (24) as a gas-liquid separator, and a decompressor. And an intermediate heat exchanger (1) for exchanging heat between the refrigerant coming out of the gas cooler (22) and the refrigerant coming out of the evaporator (23). The supercritical refrigeration cycle is mounted on a vehicle such as an automobile as a car air conditioner.

  The low-pressure refrigerant that has flowed out of the evaporator (23) and passed through the accumulator (24) flows in the first fluid passage (6) of the intermediate heat exchanger (1), and in the second fluid passage (7), the gas cooler ( The high-pressure refrigerant from 22) flows. Then, the refrigerant flowing in the first fluid passage (6) is mixed in the fluid mixing section (20) together with the inertial force when passing through each bending portion (10A), so that the turbulent flow The heat exchange performance between the refrigerants flowing in the fluid passages (6) and (7) is improved by the effect and the fluid temperature equalization effect.

  FIG. 6 shows the heat exchanger (1) of the first embodiment (Example) and a heat exchanger having the same configuration as the heat exchanger (1) of the Example except that the heat exchanger (1) is entirely straight. The heat exchange performance with (comparative example) is shown. Here, the substantial length of the heat exchange part (10) including the bent part (10A) in the heat exchanger (1) of the example is equal to the linear length of the heat exchange part of the heat exchanger of the comparative example. From the results shown in FIG. 6, it can be seen that the heat exchange performance of the heat exchanger (1) of the example is superior to the heat exchanger of the comparative example.

  FIG. 7 shows a second embodiment of the heat exchanger according to the present invention.

  In the case of the heat exchanger (30) of the embodiment shown in FIG. 7, the heat exchange section (10), that is, both pipes (2) and (3) are bent at at least one place, here three places. In each bent part (10A), the heat exchanging part (10) is bent in one plane (P1) (P2) (P3) including the axis of both pipes (2) (3). These planes (P1), (P2), and (P3) intersect each other.

  Although not shown, as in the case of the first embodiment described above, in each bent portion (10A), the outer tube (2) is bent on the plane (P1) (P2) (P3). It is slightly crushed in the direction connecting the center and the axis of the outer tube (2). And in the cross section of the bent portion (10A) of the heat exchange section (10), that is, the cross section orthogonal to the plane (P1) (P2) (P3), some of the fins (4) of the inner pipe (3) The tip is in contact with the inner peripheral surface of the bent inner part (2a) and the bent outer part (2b) of the outer pipe (2), and the bent inner part (2a) and the bent outer part (2) of the outer pipe (2) ( By 2b), the inner tube (3) is clamped and fixed via the fin (4). In addition, in the cross section of the bent portion (10A) of the heat exchange section (10), the tips of some fins (4) contact the bent inner portion (2a) and the bent outer portion (2b) of the outer tube 82). On both sides of the contacting portion in the circumferential direction, the gap between the tip of the fin (4) and the outer peripheral surface of the outer tube (2) is the tip of the fin (4) in the linear portion (10B). And between the outer peripheral surface of the outer pipe (2) and the fluid mixing part (20). Here, since the planes (P1), (P2), and (P3) cross each other, the position of the fluid mixing part (20) of each bent part (10A) is determined by both pipes (2) (3) The circumferential direction is different.

  Other configurations are the same as those of the heat exchanger (1) of the first embodiment, and are suitably used as an intermediate heat exchanger of a supercritical refrigeration cycle, as in the case of the first embodiment. When used as an intermediate heat exchanger, the position of the fluid mixing part (20) of each bent part (10A) is different in the circumferential direction of both pipes (2) and (3). ) The refrigerant flowing in the fluid is mixed more efficiently in the fluid mixing part (20) in combination with the inertial force when passing through each bending part (10A), and the turbulent flow effect and the uniform fluid temperature are obtained. The effect of improving the heat exchange performance between the refrigerants flowing in the two fluid passages (6) and (7) due to the effect of the conversion is superior to that in the first embodiment.

  FIG. 8 shows a heating cycle using the above-described heat exchangers (1) and (30) as a heat exchanger for heating a coolant and using a supercritical heat medium.

In FIG. 8, the heating cycle uses CO ₂ as the supercritical heat medium. The compressor (50), the high-temperature and high-pressure heat medium compressed by the compressor (50), and the engine (51) to the heater core (52). Heat exchanger (1) (30) for heating the coolant that exchanges heat with the engine coolant being sent, expansion as a pressure reducer that depressurizes the heat medium that has passed through the heat exchangers (1) and (30) for heating the coolant The valve (53), the outdoor heat exchanger (54) that evaporates the heat medium depressurized by the expansion valve (53), and the liquid in the heat medium sent from the outdoor heat exchanger (54) to the compressor (50) are separated. An accumulator (55) is provided as a gas-liquid separator. The heating cycle is mounted on a vehicle such as an automobile as a car air conditioner.

  The engine coolant flows in the first fluid passage (6) of the heat exchanger (1) (30) for heating the coolant, and the high-temperature and high-pressure compressed in the second fluid passage (7) by the compressor (50). Heat medium is flowing.

  In this heating cycle, as the compressor (50), the expansion valve (53) and the accumulator (55), the compressor (21) of the supercritical refrigeration cycle shown in FIG. 5, the expansion valve (25) as a decompressor and the gas-liquid Piping and a switching valve may be provided so that the accumulator (24) as a separator is shared and the gas cooler (22) is shared as an outdoor heat exchanger (54).

  In the above, carbon dioxide is used as the supercritical refrigerant and the supercritical heat medium, but is not limited to this, and ethylene, ethane, nitrogen oxide, and the like can also be used.

1 is an overall perspective view showing a first embodiment of a heat exchanger according to the present invention. FIG. 1A is an enlarged sectional view taken along line AA. It is a BB line expanded sectional view of Drawing 1. FIG. 3 is an enlarged cross-sectional view taken along the line CC in FIG. 1. It is a figure which shows the supercritical refrigerating cycle which used the heat exchanger of 1st Embodiment as an intermediate heat exchanger. It is a graph which shows the experiment example and comparative example which were performed using the heat exchanger of 1st Embodiment. It is a whole perspective view which shows 2nd Embodiment of the heat exchanger by this invention. It is a figure which shows the heating cycle which used the heat exchanger of 1st and 2nd embodiment as a heat exchanger for coolant heating.

Explanation of symbols

(1) (30): Heat exchanger
(2): Outer pipe
(2a): Bending inner part
(2b): Bending outer part
(3): Inner pipe
(4): Fin
(5): Connector
(6): First fluid passage
(7): Second fluid passage
(10): Heat exchange section
(10A): Bent part
(20): Fluid mixing section
(21): Compressor
(22): Gas cooler
(23): Evaporator
(24): Accumulator (gas-liquid separator)
(25): Expansion valve (pressure reducer)
(50): Compressor
(51): Engine
(52): Heater core
(53): Expansion valve (pressure reducer)
(54): Outdoor heat exchanger
(55): Accumulator (gas-liquid separator)
(P) (P1) (P2) (P3): Plane

Claims (14)

It is fixed to both ends of the outer tube, the inner tube provided at intervals in the outer tube, and the heat exchange part composed of fins provided between the outer tube and the inner tube, and both the inner and outer tubes of the heat exchange unit. A heat exchanger in which the gap between the outer tube and the inner tube of the heat exchange section serves as a first fluid passage and the inside of the inner tube serves as a second fluid passage. A heat exchanger in which the heat exchange part is bent at at least one place. The heat exchanger according to claim 1, wherein the fins are integrally formed so as to be circumferentially spaced on the outer peripheral surface of the inner tube and to extend in the length direction of the inner tube. In the cross section of the bent portion of the heat exchanging portion, the tips of some fins are in contact with the inner peripheral surfaces of the bent inner portion and the bent outer portion of the outer tube, and the bent inner portion and the bent outer portion of the outer tube. The heat exchanger according to claim 2, wherein the inner tube is sandwiched and fixed via a fin. In the cross section of the bent part of the heat exchange part, the tip of each fin is located on both sides in the circumferential direction of the part where the tip part of the fin is in contact with the inner peripheral surface of the bent inner part and the outer bent part of the outer tube. The heat exchanger according to claim 3, wherein a fluid mixing part in which a gap is formed between the part and the inner peripheral surface of the outer pipe is provided. The heat exchanging portion has a plurality of bent portions, and the bent portion is bent in one plane including the axes of both the inner and outer tubes, and the other one plane including the axes of both the inner and outer tubes and intersecting the plane. The heat exchanger according to any one of claims 1 to 4, wherein a bent portion bent inside is mixed. The heat exchanger according to any one of claims 1 to 5, wherein the outer tube, the inner tube, and the connector are each made of aluminum. Refrigeration having a compressor, a gas cooler, an evaporator, a gas-liquid separator, a decompressor, and an intermediate heat exchanger for exchanging heat between the refrigerant coming out of the gas cooler and the refrigerant coming out of the evaporator A refrigeration cycle comprising the heat exchanger according to any one of claims 1 to 6, wherein the intermediate heat exchanger is a cycle. 8. The refrigeration according to claim 7, wherein the low-pressure refrigerant coming out of the evaporator flows in the first fluid passage of the intermediate heat exchanger, and the high-pressure refrigerant coming out of the gas cooler also flows in the second fluid passage. cycle. The refrigeration cycle according to claim 7 or 8, wherein the supercritical refrigerant comprises carbon dioxide. A vehicle in which the refrigeration cycle according to any one of claims 7 to 9 is mounted as a car air conditioner. A compressor, an outdoor heat exchanger, a gas-liquid separator, a decompressor, and a heat exchanger for heating a coolant that exchanges heat between the high-temperature and high-pressure heat medium compressed by the compressor and the engine coolant sent from the engine to the heater core. A heating cycle comprising a heat exchanger according to any one of claims 1 to 6, wherein the heating cycle uses a supercritical heat medium, and the coolant heating heat exchanger is a heat exchanger according to any one of claims 1 to 6. The heating according to claim 11, wherein the engine coolant flows in the first fluid passage of the heat exchanger for heating the coolant, and the high-temperature and high-pressure heat medium compressed by the compressor flows in the second fluid passage. cycle. The heating cycle according to claim 11 or 12, wherein the supercritical heat medium comprises carbon dioxide. A vehicle in which the heating cycle according to any one of claims 11 to 13 is mounted as a car air conditioner.

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