JP2012225612A - Intermediate heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate heat exchanger usable for an air conditioning device, which can prevent deterioration in refrigerant condensation efficiency of a capacitor and save a space.SOLUTION: The intermediate heat exchanger 10 includes: an outer tube 15; and an inner tube 16 arranged with a spacing in the outer tube 15, and further includes: a double tube 11 in which a gap between the outer tube 15 and the inner tube 16 is a high-temperature side refrigerant passage 12, and the inside of the inner tube 13 is a low-temperature side refrigerant passage 13; and a longitudinal reservoir 14 which is provided to be connected to the inside of the high-temperature side refrigerant passage 12 of the double tube 11, and reserves the high-pressure refrigerant flowing from the capacitor before decompressed by a decompressor to separate a liquid phase and a gas phase. The double tube 11 has a longitudinal part 20. The longitudinal reservoir 14 is arranged along the longitudinal part of the double tube 11. The longitudinal part 20 of the refrigerant goes into the longitudinal reservoir 14 from the high-temperature side refrigerant passage 12 of the double tube 11, and returns to the high-temperature side refrigerant passage 12 from the longitudinal reservoir 14.

Description

  The present invention relates to an intermediate heat exchanger used for an air conditioner mounted on a vehicle, for example.

  In this specification and claims, the term “liquid phase refrigerant” means a liquid phase refrigerant in which a trace amount of a gas phase refrigerant is mixed in addition to a refrigerant consisting entirely of a liquid phase. The term “gas-phase refrigerant” means a gas-phase refrigerant in which a very small amount of liquid-phase refrigerant is mixed in addition to a refrigerant consisting entirely of the gas phase. In this specification and claims, the top and bottom of FIGS. 2, 4, 5 and 7 are referred to as the top and bottom.

  Hereinafter, the same portions and the same parts are denoted by the same reference numerals throughout the drawings, and redundant description is omitted.

  For example, as a vehicle air conditioner mounted on a vehicle, as shown in FIG. 8, a compressor (1), a condenser (2) for cooling the refrigerant compressed by the compressor (1), and a condenser (2) It has an expansion valve (3) as a decompressor for decompressing the cooled refrigerant, an evaporator (4) for evaporating the decompressed refrigerant, a high-temperature side refrigerant passage (6), and a low-temperature side refrigerant passage (7). Heat exchange between the high-temperature and high-pressure refrigerant flowing out of the condenser (2) and flowing in the high-temperature side refrigerant passage (6) and the low-temperature and low-pressure refrigerant flowing out of the evaporator (4) and flowing in the low-temperature side refrigerant passage (7). The high-temperature and high-pressure refrigerant that flows out of the condenser (2) and is decompressed by the expansion valve (3) is stored and separated into a liquid phase and a gas phase. A liquid reservoir (8), the liquid reservoir (8) is provided between the condenser (2) and the intermediate heat exchanger (5), and the refrigerant is a double-pipe heat exchanger ( Before entering the high-temperature side refrigerant passage (6) of 5), the high-temperature side refrigerant passage of the double-pipe heat exchanger (5) enters the liquid reservoir (8) and exits from the liquid reservoir (8). A vehicle air conditioner configured to flow into (6) is known (see Patent Document 1).

  In the vehicle air conditioner described in Patent Document 1, the high-temperature and high-pressure refrigerant (see FIG. 9 state A) compressed by the compressor (1) is cooled in the condenser (2) (see FIG. 9 state B). The cooled refrigerant flows into the liquid reservoir (8) and is separated into a liquid phase and a gas phase. The refrigerant flowing out of the liquid reservoir (8) flows into the high-temperature side refrigerant passage (6) of the double-pipe heat exchanger (5) and flows from the evaporator (4) when flowing through the high-temperature side refrigerant passage (6). It is supercooled by the relatively low temperature refrigerant that flows out and flows through the low temperature side refrigerant passage (7) (see state C in FIG. 9). The high-pressure refrigerant supercooled in the double-pipe heat exchanger (5) is adiabatically expanded and decompressed in the expansion valve (3) (see state D in FIG. 9). The decompressed refrigerant enters the evaporator (4), and cools the air flowing through the ventilation gap while flowing through the evaporator (4) to become a gas phase (see state E in FIG. 9). The relatively low-temperature refrigerant that has passed through the evaporator (4) passes through the low-temperature side refrigerant passage (7) of the double-pipe heat exchanger (5). The low-temperature side refrigerant passing through the low-temperature side refrigerant passage (7) of the double-pipe heat exchanger (5) is overheated by the high-temperature side refrigerant flowing through the high-temperature side refrigerant passage (6) and the temperature is raised (FIG. 9). In this state, it is sent to the compressor (1) and compressed.

  Incidentally, in the vehicle air conditioner described in Patent Document 1, it is the refrigerant in the state B of FIG. 9 that flows into the liquid reservoir (8), but in the liquid reservoir (8), the liquid phase and the gas phase are separated. In order to perform the separation efficiently, the liquid phase refrigerant in the liquid reservoir (8) needs to be stably maintained in a liquid phase state without changing to a gas phase refrigerant. In order to stably maintain the liquid phase refrigerant in the liquid phase without changing it to the gas phase refrigerant in the liquid reservoir (8), the refrigerant flowing into the liquid reservoir (8) is actually 3 It is necessary to supercool about ~ 5 ° C. Therefore, in the vehicle air conditioner described in Patent Document 1, it is necessary to supercool the refrigerant in the condenser (2) by about 3 to 5 ° C. However, when the refrigerant is supercooled in the condenser (2), if the area of the effective core part is constant, the area of the part contributing to the condensation of the refrigerant must be reduced, and the refrigerant condensation in the condenser (2) Efficiency is reduced. In addition, when the refrigerant condensing efficiency of the condenser (2) is reduced, it is necessary to reduce the amount of refrigerant circulating in the vehicle air conditioner, and the cooling capacity is reduced. Further, when the refrigerant is supercooled in the condenser (2), there is a problem that the supercooling efficiency varies greatly depending on the wind speed and wind speed distribution received and the outside air temperature.

JP 2005-22601 A

  An object of the present invention is to provide an intermediate heat exchanger for use in an air conditioner that can solve the above-described problems, prevent a reduction in refrigerant condensation efficiency of a condenser, and save space.

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

1) In an air conditioner including a compressor, a condenser that cools the refrigerant compressed by the compressor, a decompressor that decompresses the refrigerant cooled by the condenser, and an evaporator that evaporates the decompressed refrigerant, An intermediate heat exchanger used for heat exchange between the high-pressure refrigerant that has flowed out and the low-pressure refrigerant that has flowed out of the evaporator,
The outer tube and the inner tube arranged at intervals in the outer tube, and the gap between the outer tube and the inner tube is a high-temperature side refrigerant passage through which the high-pressure refrigerant flowing out of the condenser flows, The inner pipe is provided so as to communicate with the low temperature side refrigerant passage through which the low-pressure refrigerant that has flowed out of the evaporator flows, and the high temperature side refrigerant passage of the double pipe, and flows out of the condenser and the decompressor. And a liquid reservoir for storing the high-pressure refrigerant before being decompressed by the liquid phase and separating it into a liquid phase and a gas phase. The double pipe has a vertical portion, and the double pipe has an outer pipe in the vertical portion. Are provided with an outlet for allowing the refrigerant to flow out of the high-temperature side refrigerant passage and an inlet for allowing the refrigerant to flow into the high-temperature side refrigerant passage. Is the high-temperature side refrigerant passage in the vertical part of the heavy pipe? It enters the liquid reservoir, an intermediate heat exchanger that is adapted from the sump to return to the high temperature side refrigerant passage.

  2) The intermediate heat exchanger as described in 1) above, wherein a partition for dividing the high temperature side refrigerant passage into an outlet side portion and an inlet side portion is provided in the high temperature side refrigerant passage of the double pipe.

  3) The liquid reservoir is a hermetically sealed vertical tube, and the refrigerant inlet that allows the outlet of the outer pipe of the double pipe to communicate with the peripheral wall of the reservoir, and the inlet of the outer pipe of the double pipe The intermediate heat exchanger according to 1) or 2) above, wherein a refrigerant outlet is provided for allowing the refrigerant to pass through the liquid reservoir.

  4) The liquid reservoir is composed of a vertical cylindrical main body and an attachment member fixed to the vertical portion of the double pipe and attached to the lower end of the cylindrical main body, and is sealed, and the attachment member A refrigerant inflow path with one end leading to the outlet of the outer pipe of the double pipe and the other end leading into the cylindrical main body, and one end leading to the inlet of the outer pipe of the double pipe and the other end of the cylindrical main body The intermediate heat exchanger according to 1) or 2) above, wherein a refrigerant outflow passage leading to the inside is provided.

  According to the intermediate heat exchanger of 1) to 4) above, the outer pipe and the inner pipe arranged at intervals in the outer pipe are provided, and the gap between the outer pipe and the inner pipe flows out of the condenser. A double pipe in which a high-temperature refrigerant passage through which a high-pressure refrigerant flows and a low-pressure refrigerant passage in which the low-pressure refrigerant flowing out of the evaporator flows is formed in the inner pipe, and a high-temperature refrigerant passage in the double pipe And a liquid reservoir that stores the high-pressure refrigerant that flows out of the condenser and is decompressed by the decompressor and separates it into a liquid phase and a gas phase. And in the vertical portion, the outer pipe of the double pipe is provided with an outlet for allowing the refrigerant to flow out from the high temperature side refrigerant passage and an inlet for allowing the refrigerant to flow into the high temperature side refrigerant path. It is arranged along the vertical part of the Since the refrigerant enters the liquid reservoir from the high-temperature side refrigerant passage at the facing portion and returns to the high-temperature side refrigerant passage from the liquid reservoir, the refrigerant that has entered the high-temperature side refrigerant passage of the double pipe flows into the liquid reservoir. In the meantime, the refrigerant is cooled by the refrigerant flowing through the low temperature side refrigerant passage of the double pipe. Accordingly, the refrigerant can be supercooled in the double pipe before flowing into the liquid reservoir, and the liquid phase refrigerant in the liquid reservoir can be stably maintained in a liquid phase state without changing to a gas phase refrigerant. Thus, the liquid phase and the gas phase can be separated efficiently in the liquid reservoir. As a result, the entire effective core portion of the condenser of the air conditioner provided with the intermediate heat exchanger can be contributed to the condensation of the refrigerant, and a reduction in the refrigerant condensation efficiency of the condenser can be prevented. In addition, since the refrigerant condensation efficiency of the condenser can be prevented from being lowered, it is not necessary to reduce the amount of refrigerant circulating through the air conditioner, and the cooling capacity can be prevented from being lowered. In addition, since the refrigerant flowing through the low-temperature side refrigerant passage of the double pipe is supercooled in the refrigerant flowing through the high-temperature side refrigerant passage and flowing into the liquid reservoir, the subcooling of the refrigerant causes fluctuations in wind speed and outside temperature. A stable degree of supercooling can be obtained without dependence.

  In addition, since the double pipe has a vertical portion and the liquid reservoir is arranged along the vertical portion of the double pipe, space saving of the air conditioner using this intermediate heat exchanger is achieved. In addition, the dead space can be effectively used to arrange the liquid reservoir.

It is a figure which shows the structure of the vehicle air conditioner using the intermediate heat exchanger of Embodiment 1 of this invention. It is the vertical longitudinal cross-sectional view which abbreviate | omitted one part which shows the intermediate heat exchanger of Embodiment 1 of this invention. It is the sectional view on the AA line of FIG. It is the vertical longitudinal cross-sectional view which abbreviate | omitted one part which shows the intermediate heat exchanger of Embodiment 2 of this invention. It is the vertical longitudinal cross-sectional view which abbreviate | omitted one part which shows the intermediate heat exchanger of Embodiment 3 of this invention. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is the vertical longitudinal cross-sectional view which abbreviate | omitted one part which shows the intermediate heat exchanger of Embodiment 4 of this invention. It is a figure which shows the structure of the conventional vehicle air conditioner. It is a Mollier diagram of an air conditioner for vehicles.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the intermediate heat exchanger of the present invention is used for a vehicle air conditioner mounted on a vehicle.

  In the following description, left and right in FIGS. 2, 4, 5 and 7 are referred to as left and right.

  In the following description, the term “aluminum” includes aluminum alloys in addition to pure aluminum.

Embodiment 1
This embodiment is shown in FIGS.

  FIG. 1 shows the configuration of a vehicle air conditioner using the intermediate heat exchanger of the first embodiment, and FIGS. 2 and 3 show the intermediate heat exchanger of the first embodiment.

  The vehicle air conditioner shown in FIG. 1 includes a high-temperature side refrigerant passage (12) through which a high-temperature and high-pressure refrigerant flowing out from a condenser (2) flows and a low-temperature side refrigerant passage (13 ) And a double pipe (11) that leads to the high temperature side refrigerant passage (12) and flows out of the condenser (2) and is decompressed by the expansion valve (3). An intermediate heat exchanger (10) comprising a liquid reservoir (14) for storing a high-pressure refrigerant before being separated into a liquid phase and a gas phase, and accumulating the liquid phase refrigerant in a lower portion is provided.

  As shown in FIGS. 2 and 3, the double pipe (11) of the intermediate heat exchanger (10) includes an aluminum outer pipe (15) and aluminum arranged at intervals in the outer pipe (15). The inner pipe (16) is provided, the gap between the outer pipe (15) and the inner pipe (16) is a high-temperature side refrigerant passage (12), and the inner pipe (16) has a low temperature A side refrigerant passage (13) is formed. The outer pipe (15) of the double pipe (11) is provided with a refrigerant inlet (17) leading to one end in the high temperature side refrigerant passage (12) and a refrigerant outlet (18) leading to the other end. . A pipe (P1) extending from the condenser (2) is connected to the refrigerant inlet (17), and a pipe (P2) extending to the expansion valve (3) is connected to the refrigerant outlet (18). In FIG. 2, the refrigerant inlet (17) and the refrigerant outlet (18) face the same direction, here upward, but they may face different directions.

  The double pipe (11) is connected to the vertical portion (20), the upper horizontal portion (21) extending to the left and connected to the upper end of the vertical portion (20), and the lower end of the vertical portion (20). And a lower lateral portion (22) extending rightward. The vertical portion (20) means not only a vertical state but also a state inclined from the vertical to 30 degrees.

  The outer pipe (15) of the double pipe (11) includes a pipe body (23) with both ends opened, one end opened and the other end closed, and the open ends at both ends of the pipe body (23). A bottomed cylindrical closure member (24) that is joined and closes both ends of the pipe (23), and is connected to the distal end of the upper lateral portion (21) to the coolant inlet (17) to the closure member (24) And a refrigerant outlet (18) is formed in the closing member (24) joined to the tip of the lower lateral portion (22). In the vertical portion (20) of the double pipe (11), the pipe body (23) of the outer pipe (15) has an outlet (25) for letting the refrigerant flow out from the high temperature side refrigerant passage (12) and a high temperature side refrigerant. Inflow ports (26) through which the refrigerant flows into the passage (12) are formed at intervals in the vertical direction so that the former is positioned above.

  Both ends of the inner pipe (16) of the double pipe (11) protrude outward from both ends of the outer pipe (15), and the inner pipe (16) is connected to the closing member (24) of the outer pipe (15). It penetrates the bottom wall (24a). Although not shown, a pipe extending from the evaporator (4) is connected to the end of the inner pipe (16) on the refrigerant outlet (18) side, and the end of the inner pipe (16) on the refrigerant inlet (17) side is also connected. Is connected to a pipe extending to the compressor (1).

  The liquid reservoir (14) is a sealed vertical cylinder with both upper and lower ends closed, and has an aluminum bottomed cylindrical main body (27) having an upper end opened and a lower end closed, and a main body (27). The lid (28) is detachably attached to the upper end portion and closes the upper end opening of the main body (27), and is disposed along the longitudinal portion (20) of the double pipe (11). The peripheral wall of the main body (27) of the liquid reservoir (14) is provided with an arcuate recess (29) extending in the vertical direction and recessed inward, and the coolant inlet (31) is provided in the recess (29). The refrigerant outlet (32) is formed at intervals in the vertical direction so that the former is positioned above. And a part of the outer peripheral surface of the pipe body (23) in the outer pipe (15) of the double pipe (11) is an outlet (25) and a refrigerant inlet (31), and an inlet (26) and a refrigerant outlet ( 32) is in close contact with the recessed portion (29) so that the tube main body (23) and the main body (27) are joined in this state, thereby the outer tube (15) of the double tube (11). ) Outlet (25) and inlet (26) and the inside of the liquid reservoir (14). A desiccant enclosure (33) is placed in the liquid reservoir (14). A filter may be placed in the liquid reservoir (61). The desiccant enclosure (33) and the filter are not necessarily required.

  In the vehicle air conditioner shown in FIG. 1, the high-temperature and high-pressure gas-liquid mixed-phase refrigerant compressed by the compressor (1) is cooled in the condenser (2), and the double pipe (11 of the intermediate heat exchanger (10)) ) Enters the high temperature side refrigerant passage (12) from the refrigerant inlet (17) of the outer pipe (15). The refrigerant that has entered the high temperature side refrigerant passage (12) is cooled by the low temperature and low pressure refrigerant flowing in the low temperature side refrigerant passage (13) while flowing in the high temperature side refrigerant passage (12), and becomes a supercooled state. . A part of the refrigerant that has become supercooled enters the liquid reservoir (14) through the outlet (25) of the outer pipe (15) and the refrigerant inlet (31) of the liquid reservoir (14), and enters the liquid phase. While being separated into the gas phase, the moisture in the refrigerant is removed by the desiccant in the desiccant enclosure (33). The liquid phase refrigerant in the liquid reservoir (14) passes through the refrigerant outlet (32) of the liquid reservoir (14) and the inlet (26) of the outer pipe (15), and the high-temperature side refrigerant passage ( 12) Return to the inside, and sent from the refrigerant outlet (18) to the expansion valve (3). On the other hand, the refrigerant that has not entered the liquid reservoir (14) among the supercooled refrigerant is sent from the refrigerant outlet (18) to the expansion valve (3).

  Since the refrigerant flowing into the liquid reservoir (14) is in a supercooled state (see state G in FIG. 9), the liquid phase refrigerant in the liquid reservoir (14) is changed to a liquid phase state without changing to a gas phase refrigerant. It becomes possible to maintain it stably, and the liquid phase and the gas phase can be efficiently separated in the liquid reservoir (14). As a result, the entire effective core portion of the condenser (2) can be contributed to the condensation of the refrigerant, and a reduction in the refrigerant condensation efficiency of the condenser (2) can be prevented. In addition, since it is possible to prevent the refrigerant condensation efficiency of the condenser (2) from being lowered, it is not necessary to reduce the amount of refrigerant circulating through the air conditioner, and it is possible to prevent the cooling capacity from being lowered. In addition, since the refrigerant flowing through the low temperature side refrigerant passage (13) of the double pipe (11) flows through the high temperature side refrigerant passage (12) and the refrigerant flowing into the liquid reservoir (14) is supercooled, The supercooling of the refrigerant does not depend on fluctuations in the wind speed or the outside air temperature, and a stable degree of supercooling can be obtained.

  In addition, the high-temperature and high-pressure refrigerant that has flowed out of the liquid reservoir (14) and entered the high-temperature side refrigerant passage (12) of the double pipe (11), before flowing out of the refrigerant outlet (18), (13) The refrigerant is further cooled by the low-temperature and low-pressure refrigerant flowing in the interior, and is subcooled to the state C in FIG.

Embodiment 2
This embodiment is shown in FIG.

  In the case of the intermediate heat exchanger (40) shown in FIG. 4, the high temperature side refrigerant passage (12) is connected to the outlet (25) side portion and the inlet (inlet) in the high temperature side refrigerant passage (12) of the double pipe (11). 26) A partition portion (41) is provided to partition the side portion. The partition (41) is made of an annular plate inserted into the high-temperature side refrigerant passage (12) through a slit (42) formed in the pipe body (23) of the outer pipe (15). The partition part (41) may be provided by deforming at least one of the pipe body (23) and the inner pipe (16) of the outer pipe (15).

  Other configurations are the same as those of the intermediate heat exchanger (10) of the first embodiment.

  The operation of the vehicle air conditioner using the intermediate heat exchanger (40) of Embodiment 2 is sent from the condenser (2) to the high temperature side refrigerant passage (12) of the double pipe (41) from the refrigerant inlet (17). All of the refrigerant that has been cooled and cooled by the low-temperature and low-pressure refrigerant flowing in the low-temperature side refrigerant passage (13) while flowing into the high-temperature side refrigerant passage (12) enters the liquid reservoir (14 ) Is the same as the vehicle air conditioner shown in FIG.

Embodiment 3
This embodiment is shown in FIG. 5 and FIG.

  In the case of the intermediate heat exchanger (45) shown in FIGS. 5 and 6, the peripheral wall of the main body (27) of the liquid reservoir (14) is not formed with the recess (29), and the peripheral wall has a circular cross section. ing. And a portion around the outlet (25) in the pipe body (23) constituting the outer pipe (15) of the double pipe (11), and a refrigerant inlet (31) in the body (27) of the liquid reservoir (14) And a portion around the inlet (26) in the pipe main body (23) and a portion around the refrigerant outlet (32) in the main body (27) of the liquid reservoir (14), respectively, are connected members ( 46) It is joined via (47). A refrigerant channel (48) is formed in the upper connecting member (46) through the outlet (25) and the refrigerant inlet (31), and the inlet (26) and the refrigerant outlet (32) are formed in the lower connecting member (47). ) Through which the refrigerant flow path (49) is formed, and thereby the outlet (25) and the inlet (26) of the outer pipe (15) of the double pipe (11) and the liquid reservoir (14) Is allowed to communicate.

  Other configurations are the same as those of the intermediate heat exchanger (10) of the first embodiment.

  The operation of the vehicle air conditioner using the intermediate heat exchanger (45) of the third embodiment is the same as that of the vehicle air conditioner using the intermediate heat exchanger (10) of the first embodiment.

Embodiment 4
This embodiment is shown in FIG.

  In the case of the intermediate heat exchanger (50) shown in FIG. 7, the liquid reservoir (51) is closed in the vertical direction along the vertical portion (20) of the double pipe (11) with the upper end closed and the lower end open. The aluminum covered cylindrical body (52) and the vertical part (20) of the double pipe (11) are fixed to the pipe body (23) of the outer pipe (11) and the lower end of the body (52) is attached. The aluminum mounting member (53) is used, and the lower end opening of the main body (52) is closed by the mounting member (53), so that the liquid reservoir (51) is hermetically sealed.

  The attachment member (53) of the liquid reservoir (51) is provided with a recess (56) extending downward from the upper end surface. Also, the refrigerant that has one end leading to the outlet (25) of the outer pipe (15) of the double pipe (11) and the other end to the recess (56) to the mounting member (53) of the liquid reservoir (51) An inflow path (54) and a refrigerant outflow path (55) with one end leading to the inlet (26) of the outer pipe (15) of the double pipe (11) and the other end leading into the recess (56) are provided. As a result, the outlet (25) and the inlet (26) of the outer pipe (15) of the double pipe (11) communicate with the inside of the cylindrical body (52) of the liquid reservoir (51). Yes.

  Other configurations are the same as those of the intermediate heat exchanger (10) of the first embodiment.

  The operation of the vehicle air conditioner using the intermediate heat exchanger (50) of the fourth embodiment is the same as that of the vehicle air conditioner using the intermediate heat exchanger (10) of the first embodiment.

  The intermediate heat exchanger according to the present invention is suitably used for an air conditioner mounted on a vehicle.

(1): Compressor
(2): Capacitor
(3): Expansion valve (pressure reducer)
(4): Evaporator
(10) (40) (45) (50): Intermediate heat exchanger
(11): Double pipe
(12): High temperature side refrigerant passage
(13): Low temperature side refrigerant passage
(14) (51): Liquid reservoir
(15): Outer pipe
(16): Inner pipe
(20): Vertical part
(25): Outlet
(26): Inlet
(31): Refrigerant inlet
(32): Refrigerant outlet
(41): Partition
(52): Body
(53): Mounting member
(54): Refrigerant inflow path
(55): Refrigerant outflow path

Claims (4)

An air conditioner comprising a compressor, a condenser that cools the refrigerant compressed by the compressor, a decompressor that decompresses the refrigerant cooled by the condenser, and an evaporator that evaporates the decompressed refrigerant flows out of the condenser An intermediate heat exchanger used for heat exchange between a high-pressure refrigerant and a low-pressure refrigerant flowing out of an evaporator,
The outer tube and the inner tube arranged at intervals in the outer tube, and the gap between the outer tube and the inner tube is a high-temperature side refrigerant passage through which the high-pressure refrigerant flowing out of the condenser flows, The inner pipe is provided so as to communicate with the low temperature side refrigerant passage through which the low-pressure refrigerant that has flowed out of the evaporator flows, and the high temperature side refrigerant passage of the double pipe, and flows out of the condenser and the decompressor. And a liquid reservoir for storing the high-pressure refrigerant before being decompressed by the liquid phase and separating it into a liquid phase and a gas phase. The double pipe has a vertical portion, and the double pipe has an outer pipe in the vertical portion. Are provided with an outlet for allowing the refrigerant to flow out of the high-temperature side refrigerant passage and an inlet for allowing the refrigerant to flow into the high-temperature side refrigerant passage. Is the high-temperature side refrigerant passage in the vertical part of the heavy pipe? It enters the liquid reservoir, an intermediate heat exchanger that is adapted from the sump to return to the high temperature side refrigerant passage. 2. The intermediate heat exchanger according to claim 1, wherein a partition portion that divides the high temperature side refrigerant passage into an outlet side portion and an inlet side portion is provided in the high temperature side refrigerant passage of the double pipe. The liquid reservoir is a sealed vertical tube, and a refrigerant inlet that allows the outlet of the outer pipe of the double pipe to communicate with the inside of the liquid reservoir, and an inlet of the outer pipe of the double pipe are liquid. The intermediate heat exchanger according to claim 1 or 2, wherein a refrigerant outlet for communication with the reservoir is provided. The liquid reservoir is composed of a vertical cylindrical main body and an attachment member fixed to the vertical portion of the double tube and attached to the lower end portion of the cylindrical main body, and is in a sealed state. One end leads to the outlet of the outer pipe of the double pipe and the other end leads to the refrigerant main body, and one end leads to the inlet of the outer pipe of the double pipe and the other end enters the cylindrical main body. The intermediate heat exchanger according to claim 1 or 2, wherein a refrigerant outflow passage is provided.

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