JP2007163042A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger that can increase a heat radiation amount when used as a gas cooler in a supercritical refrigeration cycle. <P>SOLUTION: The heat exchanger 1 has a refrigerant inlet 12 and a refrigerant outlet 13 on an upper header section 8 and a lower header section 9 of a first header tank respectively. An average passage length L0 is defined by a numerical value represented by an expression: ä(L1+L2)/2}+(T×2N), where L1 is the total length of internal lengths Ia and Ib of both header sections 8 and 9 of the first header tank, L2 is an internal length Ic of header sections 11 of a second header tank, T is the length of flat tubes 4, and N is the number of header sections 11 of the second header tank. The refrigerant inlet 12 and refrigerant outlet 13 are positioned such that the relation of the average passage length L0 to a passage length LX for a refrigerant flowing into the upper header section 8 from the refrigerant inlet 12 and flowing out from the refrigerant outlet 13 on the header section 11 satisfies a relation: 0.8≤LX/L0≤1.2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a heat exchanger, and more particularly to a heat exchanger suitably used for a gas cooler of a supercritical refrigeration cycle in which a supercritical refrigerant such as CO ₂ (carbon dioxide) is used.

  In this specification and claims, the term “supercritical refrigeration cycle” means a refrigeration cycle in which the refrigerant is in a supercritical state exceeding the critical pressure on the high pressure side, and “supercritical refrigerant” It shall mean a refrigerant used in a supercritical refrigeration cycle.

  As a heat exchanger used in a gas cooler of a supercritical refrigeration cycle having a compressor, a gas cooler, an evaporator, a decompressor, and an intermediate heat exchanger that exchanges heat between the refrigerant that has come out of the gas cooler and the refrigerant that has come out of the evaporator, A pair of vertically extending header tanks that are spaced apart from each other, and a plurality of flat tubes that are spaced vertically between the header tanks and that are connected to both header tanks at both ends. The first header tank is provided with two upper and lower header parts, and the second header tank is provided with one header part so as to straddle two adjacent header parts of the first header tank. A refrigerant inlet is provided in the upper header portion of the first header tank, and a refrigerant outlet is provided in the lower header portion, so that all flat tubes are connected vertically. To a plurality of flat tubes arranged and two upper and lower heat exchangers are divided into path is known (see Patent Document 1).

  Moreover, as a heat exchanger used for the above-described gas cooler, a pair of header tanks extending in the vertical direction spaced apart from each other, and spaced apart in the vertical direction between both header tanks, and both end portions Are provided with a plurality of flat tubes connected to both header tanks, each header tank is provided with two upper and lower header parts, a refrigerant inlet is provided in the lower header part of the first header tank, and A heat exchanger in which a refrigerant outlet is provided in the upper header portion of the two header tanks, and all flat tubes are composed of a plurality of flat tubes arranged vertically and are divided into three paths arranged in the vertical direction. Is also known (see Patent Document 2).

  However, as a result of various studies by the present inventor, in the heat exchanger described in Patent Document 1, the refrigerant inlet and the refrigerant outlet are provided in the central portion in the length direction of the header portion. Was found to occur. That is, the refrigerant that has flowed into the upper header portion of the first header tank from the refrigerant inlet flows into a plurality of flat tubes communicating with the upper header portion, that is, into the flat tubes of the upper path, and passes through the flat tubes to be second. The first header tank flows into the header portion of the header tank, and then flows into a plurality of flat tubes connected to the lower header portion of the first header tank, that is, into the flat tubes of the lower path, and passes through the flat tubes. It flows in in the lower header part of the bottom and flows out from the refrigerant outlet. And the flow path length of the refrigerant passing through the flat tube at the height position near the refrigerant outlet in the lower path and passing through the flat tube at the height position near the refrigerant outlet in the lower path, and the upper end portion of the upper path The flow path length of the refrigerant passing through the flat tube and passing through the flat tube at the lower end of the lower path is greatly different. As a result, the balance between the flow rate and flow rate of the refrigerant flowing through each flat tube is deteriorated, and the amount of heat release is insufficient as a gas cooler of the supercritical refrigeration cycle.

Also in the heat exchanger described in Patent Document 2, since the refrigerant inlet and the refrigerant outlet are provided in the central portion in the length direction of the header portion, as in the case of the heat exchanger described in Patent Document 1, supercritical refrigeration is performed. The heat dissipation is insufficient as a cycle gas cooler.
JP 2003-279194 A JP 2004-138306 A

  This invention is made in view of the said situation, Comprising: It is providing the heat exchanger which can increase the thermal radiation amount at the time of using as a gas cooler of a supercritical refrigerating cycle.

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

1) A pair of header tanks that are spaced apart from each other, and a plurality of flat tanks that are spaced between the header tanks in the length direction of the header tank and that are connected to both header tanks at both ends. The first header tank is provided with a plurality of header portions arranged in the length direction, and the second header tank is one less than the number of header portions of the first header tank. The header portion is provided so as to straddle two adjacent header portions of the first header tank, the refrigerant inlet is provided in the header portion at one end portion in the length direction of the first header tank, and the header at the other end portion The refrigerant outlet is provided in the section, and all the flat tubes are made up of a plurality of flat tubes arranged continuously in the length direction of the header tank and are divided into the same number of paths as the number of headers of the first header tank. Exchange In,
L1 is the total internal length of all header sections in the first header tank, L2 is the total internal length of all header sections in the second header tank, T is the length of the flat tube, and the second header tank. When the number of header parts of N is defined as N, if the numerical value represented by the expression {(L1 + L2) / 2} + (T × 2N) is defined as the average flow path length L0, it flows into the first header tank from the refrigerant inlet The relationship between the flow path length LX and the average flow path length L0 when the refrigerant flows out from the refrigerant outlet through the flat tubes of all header sections and all paths is 0.8 ≦ LX / L0 ≦ 1.2 A heat exchanger in which the position of the refrigerant inlet and the position of the refrigerant outlet are determined so as to satisfy the relationship.

  2) The heat exchanger according to 1) above, wherein the number of header portions of the first header tank is 2, the number of header portions of the second header tank is 1, and the number of passes is 2.

  3) The heat exchanger according to 1) or 2) above, wherein the amount of compressor lubricant mixed in the refrigerant used is 1% by mass or less.

4) A pair of header tanks arranged at a distance from each other, and a plurality of flat tanks arranged between the header tanks in the length direction of the header tank and having both ends connected to both header tanks A plurality of header portions arranged in the length direction in the first header tank, and the same number of header portions as the header portions of the first header tank are provided in the second header tank. A refrigerant inlet is provided in the header portion at one end in the length direction of the first header tank, and is provided in the header portion at the end opposite to the refrigerant inlet in the second header tank. An outlet is provided, and all the flat tubes are made up of a plurality of flat tubes arranged in a row in the length direction of the header tanks, and are divided into one more path than the number of headers of both header tanks. Exchange In the vessel,
The total internal length of all header sections in the first header tank is L1, the total internal length of all header sections in the second header tank is L2, the flat tube length is T, When the number of header parts is N, if the numerical value represented by the expression {(L1 + L2) / 2} + {T × (N + 1)} is defined as the average flow path length L0, the refrigerant inlet to the first header tank The relationship between the flow path length LX and the average flow path length L0 when the inflowing refrigerant flows out from the refrigerant outlet through the flat tubes of all header sections and all paths is 0.8 ≦ LX / L0 ≦ 1.2. A heat exchanger in which the position of the refrigerant inlet and the position of the refrigerant outlet are determined so as to satisfy the relationship.

  5) The heat exchanger according to 4) above, wherein the number of header portions of each header tank is 2, and the number of passes is 3.

  6) The heat exchanger according to 4) or 5) above, wherein the amount of compressor lubricant mixed in the refrigerant used is 1% by mass or less.

  7) A refrigeration cycle equipped with a compressor, gas cooler, evaporator, decompressor, and intermediate heat exchanger that exchanges heat between the refrigerant coming out of the gas cooler and the refrigerant coming out of the evaporator, and that uses supercritical refrigerant. A supercritical refrigeration cycle in which the gas cooler includes the heat exchanger according to any one of 1) to 6) above.

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

  9) The heat exchanger according to 7) or 8) above, wherein the amount of compressor lubricant mixed in the supercritical refrigerant is 1% by mass or less.

  10) A vehicle equipped with the supercritical refrigeration cycle according to any one of 7) to 9) as a car air conditioner.

  According to the heat exchanger of 1) above, the total length of all header sections in the first header tank is L1, the total length of all header sections in the second header tank is L2, flat When the tube length is T and the number of header parts of the second header tank is N, the numerical value represented by the formula {(L1 + L2) / 2} + (T × 2N) is defined as the average flow path length L0. Then, the relationship between the flow path length LX when the refrigerant flowing into the first header tank from the refrigerant inlet flows out of the refrigerant outlet through the flat tubes of all header portions and all paths, and the average flow path length L0 is 0. Since the position of the refrigerant inlet and the position of the refrigerant outlet are determined so as to satisfy the relationship of 8 ≦ LX / L0 ≦ 1.2, the refrigerant passes through the flat tube at any position of each path in the heat exchanger. The flow path length LX does not differ greatly even when the Balance of flow and flow rate of the refrigerant flowing through the cube is improved. Therefore, the amount of heat released when used as a gas cooler of a supercritical refrigeration cycle is increased as compared with the heat exchangers described in Patent Documents 1 and 2.

  According to the heat exchanger of 3) above, it is possible to prevent a decrease in the amount of heat release when used as a gas cooler of a supercritical refrigeration cycle. That is, when the amount of compressor lubricant mixed in the refrigerant used exceeds 1% by mass, a large amount of refrigerant flows through the lower portion of the header section and the flat tube below each path. Even if they are substantially equal, the amount of heat release may be reduced.

  According to the heat exchanger of 4) above, the total length of all header sections in the first header tank is L1, the total length of all header sections in the second header tank is L2, flat When the tube length is T and the number of header portions of each header tank is N, the numerical value represented by the formula {(L1 + L2) / 2} + {T × (N + 1)} is the average flow path length L0. When defined, the relationship between the flow path length LX when the refrigerant flowing into the first header tank from the refrigerant inlet flows out from the refrigerant outlet through the flat tubes of all header sections and all paths, and the average flow path length L0 is Since the position of the refrigerant inlet and the position of the refrigerant outlet are determined so as to satisfy the relationship of 0.8 ≦ LX / L0 ≦ 1.2, the refrigerant passes through the flat tube at which position of each path in the heat exchanger. Even if it passes, the flow path length LX does not differ greatly. Balance of flow and flow rate of the refrigerant flowing through the flat tubes is improved. Therefore, the amount of heat released when used as a gas cooler of a supercritical refrigeration cycle is increased as compared with the heat exchangers described in Patent Documents 1 and 2.

  According to the heat exchanger of 6) above, it is possible to prevent a decrease in the amount of heat release when used as a gas cooler of a supercritical refrigeration cycle. That is, when the amount of compressor lubricant mixed in the refrigerant used exceeds 1% by mass, a large amount of refrigerant flows through the lower portion of the header section and the flat tube below each path. Even if they are substantially equal, the amount of heat release may be reduced.

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

  In the following description, the top and bottom, left and right in FIGS. 1 and 3 are referred to as top and bottom and 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 FIG. 1 and FIG.

  FIG. 1 shows the overall configuration of a heat exchanger according to the present invention, and FIG. 2 shows the flow of refrigerant in the heat exchanger.

  In FIG. 1, the heat exchanger (1) includes aluminum header tanks (2) (3) arranged in parallel in the left-right direction and extending in the vertical direction, and both header tanks (2) (3). Between a plurality of flat aluminum tubes (4) and adjacent flat tubes (4), which are arranged in parallel with a space in the vertical direction between them and whose both ends are connected to both header tanks (2) and (3), respectively. The aluminum corrugated fin (6) brazed to the flat tube (4) and the corrugated fin (6) And an aluminum side plate (7) brazed to the corrugated fin (6).

  The first header tank (2) on the right side is provided with a plurality of, in this case, two header sections (8) and (9) arranged vertically through a partition section (10) located in the middle of the height. ing. The second header tank (3) on the left side is one less than the header sections (8) and (9) of the first header tank (2), in this case, one header section (11) is the first header tank. It is provided so as to straddle two adjacent header parts (8) and (9) of (2). A refrigerant inlet (12) is provided on the peripheral wall of the upper header portion (8) of the first header tank (2), and a refrigerant outlet (13) is provided on the peripheral wall of the lower header portion (9).

  All flat tubes (4) have a right end communicating with the upper header (8) of the first header tank (2) and a left end at the upper part of the header (11) of the second header tank (3). A tube group consisting of a plurality of flat tubes (4) communicating with the right header portion of the first header tank (2) in the lower header portion (9) and the left end portion of the header section of the second header tank (3) ( 11) It is divided into the first and second two paths (P1) and (P2) (refrigerant passage group) by being divided into a tube group consisting of a plurality of flat tubes (4) leading to the lower part inside The flow direction of the refrigerant in all the flat tubes (4) constituting each path (P1) (P2) is the same, and the refrigerant flow in the flat tubes (4) of the two paths (P1) (P2) The flow direction is different. Although not shown, the flat tube (4) has a plurality of refrigerant passages arranged in the width direction in the flat tube (4), and the width direction is directed toward the ventilation direction (the front and back direction in FIG. 1). Has been placed.

When the value obtained by dividing the number of flat tubes (4) composing each path (P1) (P2) by the number of all flat tubes (4) is defined as `` tube ratio '', each path (P1) (P2) The tube ratio is preferably 0.45 to 0.55. The sum of the tube ratio of the first pass (P1) and the tube ratio of the second pass (P2) is 1. When the tube ratio is less than 0.45 or exceeds 0.55, a supercritical refrigerant such as CO ₂ is used for the heat exchanger (1), and the refrigerant pressure on the high pressure side is refrigerant. When used in a gas cooler of a supercritical refrigeration cycle that exceeds the critical pressure, there is a risk that the pressure loss generated in the flat tube (4) in either one of the paths (P1) (P2) will increase. The tube ratio of each path (P1) (P2) is preferably 0.48 to 0.52. Also in this case, the sum of the tube ratio of the first pass (P1) and the tube ratio of the second pass (P2) is 1.

  Here, assuming that the refrigerant flows in the heat exchanger (1) as shown in FIG. 2, the internal length Ia of the upper header portion (8) in the first header tank (2) and the lower header portion (9 ) Is the total length of the internal length Ib of L1 (= Ia + Ib), the total length of the internal length Ic of the header portion (11) in the second header tank (3) is L2 (= Ic), and the flat tube (4 ) Is T, and the number of header parts (11) of the second header tank (3) is N. The average value is represented by the formula {(L1 + L2) / 2} + (T × 2N). It can be defined as a flow path length L0. Then, the refrigerant that has flowed from the refrigerant inlet (12) into the upper header portion (8) of the first header tank (2) passes through all the header portions (8) (9) (11) and all the paths (P1) (P2). The relationship between the actual flow path length LX when flowing out from the refrigerant outlet (13) through the flat tube (4) and the average flow path length L0 satisfies the relationship 0.8 ≦ LX / L0 ≦ 1.2. Thus, the position of the refrigerant inlet (12) in the vertical direction (header part (8) length direction) and the position of the refrigerant outlet (13) in the vertical direction (header part (9) length direction) are determined.

  For example, when the refrigerant inlet (12) is at the position indicated by the point X1 in FIG. 2, the actual refrigerant flowing into the upper header (8) and flowing through the flat tube (4) at the upper end of the first path (P1) is shown. The channel length LX is longer than the average channel length L0 by the length Y1. On the other hand, the actual flow path length LX of the refrigerant flowing into the upper header section (8) and flowing through the flat tube (4) at the lower end of the first path (P1) is only Y1 longer than the average flow path length L0. Shorter. Therefore, the vertical position of the refrigerant inlet (12) is determined so that (L0 + Y1) / L0 and (L0−Y1) / L0 are in the range of 0.8 to 1.2. In addition, when the refrigerant outlet (13) is at the position indicated by the point X2 in FIG. 2, the actual refrigerant flowing into the lower header (9) through the flat tube (4) at the lower end of the second path (P2). The flow path length LX is longer than the average flow path length L0 by the length Y2. On the other hand, the actual flow path length LX of the refrigerant flowing into the lower header section (9) through the flat tube (4) at the upper end of the second path (P2) is Y2 longer than the average flow path length L0. Only shortened. Therefore, the vertical position of the refrigerant outlet (13) is determined so that (L0 + Y2) / L0 and (L0−Y2) / L0 are within the range of 0.8 to 1.2.

Embodiment 2
This embodiment is shown in FIG. 3 and FIG.

  FIG. 3 shows the overall configuration of the heat exchanger according to the present invention, and FIG. 4 shows the flow of refrigerant in the heat exchanger.

  In the heat exchanger (20) of this embodiment, the left header tank is the first header tank (21), and the right header tank is the second header tank (22). The first header tank (21) is provided with a plurality of, in this case, two header parts (24), (25) arranged vertically through a partition part (23) located above the middle of the height. It has been. In the second header tank (22), the same number of header portions (27) and (28) as the header portions (24) and (25) of the first header tank (21) are located below the middle of the height. They are arranged side by side in the vertical direction via the partition (26). A refrigerant inlet (12) is provided in the peripheral wall of the upper header portion (22) of the first header tank (21), and a refrigerant outlet (13 is provided in the peripheral wall of the lower header portion (28) of the second header tank (22). ) Is provided.

All flat tubes (4) have a left end communicating with the upper header portion (24) of the first header tank (21) and a right end portion of the upper header portion (27) of the second header tank (22). A tube group consisting of a plurality of flat tubes (4) leading to the upper end of the lower header portion (25) of the first header tank (21) and the right end portion of the second header tank (22) A tube group consisting of a plurality of flat tubes (4) leading to the lower part in the upper header part (27), and the left end part leading to the lower part in the lower header part (25) of the first header tank (21) and the right end part Are divided into a tube group consisting of a plurality of flat tubes (4) communicating with the lower header portion (28) of the second header tank (22), whereby the first to third three passes (P1) ( P2) (P3) (refrigerant passage group), and the refrigerant flow in all flat tubes (4) constituting each path (P1) (P2) (P3) Direction together with are the same, the flow direction of the refrigerant in the two paths adjacent (P1) (P2) and (P2) (P3) of the flat tubes (4) are different.
When the value obtained by dividing the number of flat tubes (4) composing each path (P1) (P2) (P3) by the number of all flat tubes (4) is defined as `` tube ratio '', each path (P1) ( The tube ratio of P2) and (P3) is 0.3 to 0.4. When the tube ratio is less than 0.3 or exceeds 0.4, a supercritical refrigerant such as CO ₂ is used for the heat exchanger (20), and the refrigerant pressure on the high pressure side is refrigerant. When used in a gas cooler of a supercritical refrigeration cycle that exceeds the critical pressure, there is a risk that the pressure loss generated in the flat tube (4) in any of the paths (P1, P2, P3) will increase. The tube ratio of each pass is preferably 0.32 to 0.0.34.

  Other configurations are the same as those in the first embodiment, and the same components are denoted by the same reference numerals and redundant description is omitted.

  Here, if the refrigerant flows in the heat exchanger (1) as shown in FIG. 4, the internal length Id of the upper header portion (24) in the first header tank (21) and the lower header portion (25 ) Is the total length of the internal length Ie of L1 (= Id + Ie), the internal length If of the upper header portion (27) in the second header tank (22) and the internal length Ig of the lower header portion (28) When the total length is L2 (= If + Ig), the length of the flat tube is T, and the number of header parts (24) (25) (27) (28) of each header tank (21) (22) is N, A numerical value represented by the expression {(L1 + L2) / 2} + {T × (N + 1)} can be defined as an average flow path length L0. Then, the refrigerant flowing into the upper header portion (24) of the first header tank (21) from the refrigerant inlet (12) passes through all the header portions (24) (25) (27) (28) and all the paths (P1) ( The relationship between the actual flow path length LX and the average flow path length L0 when flowing out from the refrigerant outlet (13) through the flat tube (4) of P2) and (P3) is 0.8 ≦ LX / L0 ≦ 1 .2 position of the refrigerant inlet (12) in the vertical direction (header part (24) length direction) and the position of the refrigerant outlet (13) in the vertical direction (header part (28) length direction) Is decided.

  For example, when the refrigerant inlet (12) is at the position indicated by the point X3 in FIG. 4, it flows into the upper header portion (24) of the first header tank (21) and enters the flat tube at the upper end of the first path (P1) ( The actual flow path length LX of the refrigerant flowing through 4) is longer by the length Y3 than the average flow path length L0. On the other hand, the actual flow path length LX of the refrigerant flowing into the upper header section (24) of the first header tank (21) and flowing through the flat tube (4) at the lower end of the first path (P1) is the average flow path length. It is shorter than L0 by length Y3. Therefore, the vertical position of the refrigerant inlet (12) is determined so that (L0 + Y3) / L0 and (L0−Y3) / L0 are in the range of 0.8 to 1.2. Further, when the refrigerant outlet (13) is at the position indicated by the point X4 in FIG. 4, the lower header portion (2) of the second header tank (22) passes through the flat tube (4) at the lower end of the third path (P3). The actual flow path length LX of the refrigerant that has flowed into 28) is longer than the average flow path length L0 by the length Y4. On the other hand, the actual flow path length LX of the refrigerant flowing into the lower header section (28) of the second header tank (22) through the flat tube (4) at the upper end of the third path (P3) is the average flow path. It is shorter than the length L0 by the length Y4. Therefore, the vertical position of the refrigerant outlet (13) is determined so that (L0 + Y4) / L0 and (L0−Y4) / L0 are in the range of 0.8 to 1.2.

The heat exchangers (1) and (20) of Embodiments 1 and 2 include a compressor, a gas cooler, an evaporator, an accumulator as a gas-liquid separator, an expansion valve as a decompressor, and a high-temperature and high-pressure refrigerant that has come out of the gas cooler. It is suitably used as a gas cooler in a supercritical refrigeration cycle that includes an intermediate heat exchanger that exchanges heat with a low-temperature and low-pressure refrigerant that has exited an evaporator and passed through an accumulator, and that uses a supercritical refrigerant made of CO ₂ . In such a supercritical refrigeration cycle, the amount of compressor lubricating oil mixed in the supercritical refrigerant is preferably 1% by mass or less.

The supercritical refrigeration cycle is mounted on a vehicle such as an automobile as a car air conditioner. Note that CO ₂ is used as a supercritical refrigerant in the supercritical refrigeration cycle, but is not limited to this, and ethylene, ethane, nitrogen oxide, and the like can also be used.

  Next, an example of an experiment performed using the heat exchanger of Embodiment 1 is shown.

Experimental example 1
The height Hc of the heat exchange core part consisting of the flat tube (4) and the corrugated fin (6): 380 mm, the width Wc of the heat exchange core part: 660 mm, the width of the flat tube (4): 16 mm, the flat tube (4) Total number: 51, number of flat tubes (4) in the first pass (P1): 26 (tube ratio 0.51), number of flat tubes (4) in the second pass (P2): 25 (tubes) The ratio LX / L0 of the flow path length LX to the average flow path length L0 is variously changed by using a heat exchanger having a ratio of 0.49), and the inlet air temperature (of the air flowing into the heat exchange core section) is changed. Temperature): 35 to 40 ° C., front wind speed (flow velocity of air flowing into the heat exchange core): 1.5 to 2.5 m / S.

  FIG. 5 shows the relationship between the ratio LX / L0 and the heat dissipation amount. From the results shown in FIG. 5, it is understood that the heat dissipation performance of the heat exchanger is excellent when the ratio LX / L0 is in the range of 0.8 to 1.2.

It is a whole front view which shows Embodiment 1 of the heat exchanger by this invention. It is a figure which shows the flow of the refrigerant | coolant in the heat exchanger of FIG. It is a whole front view which shows Embodiment 2 of the heat exchanger by this invention. It is a figure which shows the flow of the refrigerant | coolant in the heat exchanger of FIG. 6 is a graph showing the results of Experimental Example 1.

Explanation of symbols

(1) (20): Heat exchanger
(2) (21): First header tank
(3) (22): Second header tank
(4): Flat tube
(8) (9) (11) (24) (25) (27) (28): Header
(12): Refrigerant inlet
(13): Refrigerant outlet
(P1) (P2) (P3): Path
Ia to Ig: Internal length of header part T: Length of flat tube

Claims (10)

A pair of header tanks that are spaced apart from each other, and a plurality of flat tubes that are spaced between the header tanks in the length direction of the header tank and that are connected to both header tanks at both ends. The first header tank is provided with a plurality of header portions arranged in the length direction, and the second header tank has a header portion that is one less than the number of header portions of the first header tank. Is provided so as to straddle two adjacent header portions of the first header tank, and a refrigerant inlet is provided at one header portion in the length direction of the first header tank, and at the header portion at the other end portion. A heat exchanger provided with a refrigerant outlet, wherein all flat tubes are composed of a plurality of flat tubes arranged continuously in the length direction of the header tank, and are divided into the same number of paths as the number of headers of the first header tank. Oite,
L1 is the total internal length of all header sections in the first header tank, L2 is the total internal length of all header sections in the second header tank, T is the length of the flat tube, and the second header tank. When the number of header parts of N is defined as N, if the numerical value represented by the expression {(L1 + L2) / 2} + (T × 2N) is defined as the average flow path length L0, it flows into the first header tank from the refrigerant inlet The relationship between the flow path length LX and the average flow path length L0 when the refrigerant flows out from the refrigerant outlet through the flat tubes of all header sections and all paths is 0.8 ≦ LX / L0 ≦ 1.2 A heat exchanger in which the position of the refrigerant inlet and the position of the refrigerant outlet are determined so as to satisfy the relationship. The heat exchanger according to claim 1, wherein the number of header parts of the first header tank is 2, the number of header parts of the second header tank is 1, and the number of passes is 2. The heat exchanger according to claim 1 or 2, wherein a mixing amount of the compressor lubricating oil into the refrigerant to be used is 1% by mass or less. A pair of header tanks that are spaced apart from each other, and a plurality of flat tubes that are spaced between the header tanks in the length direction of the header tank and that are connected to both header tanks at both ends. The first header tank is provided with a plurality of header portions arranged in the length direction, and the second header tank has the same number of header portions as the header portions of the first header tank. The refrigerant inlet is provided in the header portion at one end in the length direction of the first header tank, and the refrigerant outlet is provided at the header portion at the end opposite to the refrigerant inlet in the second header tank. Heat exchange is provided, and all flat tubes are composed of a plurality of flat tubes arranged in a row in the length direction of the header tanks, and are divided into one more path than the number of headers in both header tanks. In,
The total internal length of all header sections in the first header tank is L1, the total internal length of all header sections in the second header tank is L2, the flat tube length is T, When the number of header parts is N, if the numerical value represented by the expression {(L1 + L2) / 2} + {T × (N + 1)} is defined as the average flow path length L0, the refrigerant inlet to the first header tank The relationship between the flow path length LX and the average flow path length L0 when the inflowing refrigerant flows out from the refrigerant outlet through the flat tubes of all header sections and all paths is 0.8 ≦ LX / L0 ≦ 1.2. A heat exchanger in which the position of the refrigerant inlet and the position of the refrigerant outlet are determined so as to satisfy the relationship. The heat exchanger according to claim 4, wherein the number of header portions of each header tank is two and the number of passes is three. The heat exchanger according to claim 4 or 5, wherein a mixing amount of the compressor lubricating oil into the refrigerant to be used is 1% by mass or less. A compressor, a gas cooler, an evaporator, a decompressor, and a refrigeration cycle that includes an intermediate heat exchanger that exchanges heat between the refrigerant that has come out of the gas cooler and the refrigerant that has come out of the evaporator, and uses a supercritical refrigerant, A supercritical refrigeration cycle, wherein the gas cooler comprises the heat exchanger according to any one of claims 1 to 6. The supercritical refrigeration cycle according to claim 7, wherein the supercritical refrigerant comprises carbon dioxide. The heat exchanger according to claim 7 or 8, wherein the amount of compressor lubricating oil mixed in the supercritical refrigerant is 1% by mass or less. A vehicle on which the supercritical refrigeration cycle according to any one of claims 7 to 9 is mounted as a car air conditioner.

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