Cold storage heat exchanger

A cold storage heat exchanger includes: a plurality of refrigerant tubes disposed at intervals, each of the refrigerant tubes including a refrigerant passage that allows a refrigerant to flow therethrough; a cold storage material adjacent to the refrigerant tubes; and a heat transfer suppressor that suppresses heat transfer from the refrigerant tubes to the cold storage material in an overheated area of the refrigerant formed in the refrigerant passage.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/JP2016/077976 filed on Sep. 23, 2016 and published in Japanese as WO 2017/057174 A1 on Apr. 6, 2017. This application is based on and claims the benefit of priority from Japanese Patent Application No. 2015-195818 filed on Oct. 1, 2015 and Japanese Patent Application No. 2016-173410 filed on Sep. 6, 2016. The entire disclosures of all of the above applications are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a cold storage heat exchanger to evaporate refrigerant, which configures a refrigerating cycle together with a compressor compressing and discharging refrigerant, a radiator cooling high-temperature refrigerant, and a decompressor decompressing the cooled refrigerant.

BACKGROUND ART

A refrigerating cycle apparatus has been conventionally used in an air conditioner. Many attempts have been made to provide a limited cooling operation even when the refrigerating cycle apparatus is in a stopped state. For example, in a vehicle air conditioner, a refrigerating cycle apparatus is driven by an engine for traveling. Thus, when the engine comes to a stop during a temporal stop of the vehicle, the refrigerating cycle apparatus also comes to a stop. There has been proposed a cold storage heat exchanger that includes a cold storage material added to an evaporator of a refrigerating cycle apparatus in order to provide a limited cooling operation during such a temporal stop of the vehicle. For example, a cold storage heat exchanger described in Patent Literature 1 is known.

PRIOR ART LITERATURES

Patent Literature

Patent Literature 1: JP 2010-91250 A

SUMMARY OF INVENTION

Typically, in a refrigerating cycle apparatus, a compressor for compressing and ejecting a refrigerant is present on the downstream side in the flow of the refrigerant relative to a cold storage heat exchanger. A return of the refrigerant in a liquid state to the compressor causes a failure. Thus, it is typically necessary to completely evaporate the refrigerant at an outlet of the cold storage heat exchanger. In the cold storage heat exchanger, the refrigerant forms a single gas layer near an outlet of a refrigerant passage, and the pressure thereof exceeds the saturated vapor pressure. As a result, there is a part where a refrigerant temperature rapidly transitions to a high temperature, that is, an overheated area. Further, when a flow rate of the refrigerant is low, there may be an imbalance in the flow of the refrigerant depending on the arrangement of the refrigerant passage inside the cold storage heat exchanger, which may form an overheated area in a part where the refrigerant is difficult to flow. In this manner, an overheated area may be present at any location on the refrigerant passage in the cold storage heat exchanger.

In the conventional cold storage heat exchanger described in Patent Literature 1, a cold storage material is typically disposed adjacent to a refrigerant tube that constitutes a refrigerant passage and cooled by a refrigerant flowing through the refrigerant tube. The inventor has made a close study and found out the following issue. When an overheated area is formed on a refrigerant tube, the temperature of a refrigerant in the overheated area becomes high. Thus, a cold storage material is less cooled due to the influence of the overheated area. As a result, a cold storage performance of the cold storage heat exchanger may be deteriorated.

It is an object of the present disclosure to provide a cold storage heat exchanger which can secure a cold storage performance, while there is an overheated area, by reducing influence of the overheated area.

According to an aspect of the present disclosure, a cold storage heat exchanger includes: a plurality of refrigerant tubes disposed at intervals, each of the refrigerant tubes including a refrigerant passage that allows a refrigerant to flow therethrough; a cold storage material adjacent to the refrigerant tubes; and a heat transfer suppressor that suppresses heat transfer from the refrigerant tubes to the cold storage material in an overheated area of the refrigerant formed in the refrigerant passage.

The above structure makes it possible to suppress heat transfer from the refrigerant tubes to the cold storage material in the overheated area of the refrigerant formed in the refrigerant passage. Thus, it is possible to avoid a situation in which the cold storage material is less cooled due to the influence of the overheated area where the refrigerant temperature becomes high. As a result, even when there is an overheated area, it is possible to ensure the cold storage performance by reducing the influence of the overheated area.

According to the present disclosure, a cold storage heat exchanger can be provided, which can secure a cold storage performance, while there is an overheated area, by reducing influence of the overheated area.

DESCRIPTION OF EMBODIMENTS

Hereinbelow, embodiments will be described with reference to the accompanying drawings. In order to facilitate the understanding of description, identical elements are designated by identical reference signs as far as possible throughout the drawings, and redundant description will be omitted.

First Embodiment

A first embodiment will be described with reference toFIGS. 1 to 10. A refrigerating cycle apparatus1is used in a vehicle air conditioner. As illustrated inFIG. 1, the refrigerating cycle apparatus1includes a compressor10, a radiator20, a pressure reducer30, and an evaporator40. These components are annularly connected to each other through piping to constitute a refrigerant circulation passage. In the refrigerating cycle apparatus1, a cold storage heat exchanger according to the first embodiment is used as the evaporator40. In the following description, the cold storage heat exchanger40according to the present embodiment is also referred to as the “evaporator40”.

The compressor10is driven by an internal combustion engine which is a power source2for traveling of a vehicle. Thus, when the power source2comes to a stop, the compressor10also comes to a stop. The compressor10draws a refrigerant from the evaporator40, compresses the drawn refrigerant, and ejects the compressed refrigerant to the radiator20.

The radiator20cools the high-temperature refrigerant. The radiator20is also called a condenser. The pressure reducer30reduces the pressure of the refrigerant cooled by the radiator20. The pressure reducer30may be provided as a fixed orifice, a temperature expansion valve, or an ejector.

The evaporator40evaporates the refrigerant with the pressure reduced by the pressure reducer30and cools a medium. The evaporator40cools air supplied to a vehicle cabin. The refrigerating cycle apparatus1may further include an internal heat exchanger which performs heat exchange between a high-pressure side liquid refrigerant and a low-pressure side gas refrigerant and a tank element such as a receiver or an accumulator which stores an excessive refrigerant. The power source2may be provided as an internal combustion engine or an electric motor.

The structure of the evaporator40as the cold storage heat exchanger according to the first embodiment will be described with reference toFIGS. 2 to 10. In the following description, an up-down direction on the sheets ofFIGS. 2 and 3is referred to as a “height direction”, an upper side in the height direction is referred to as an “upper side”, and a lower side in the height direction is referred to as a “lower side”. Although the height direction is typically the gravity direction, the height direction may be another direction. A right-left direction on the sheet ofFIG. 2is referred to as an “inflow direction” in which a refrigerant flows, a right side in the inflow direction is referred to as a “front side”, and a left side in the inflow direction is referred to as a “back side”. A right-left direction on the sheet ofFIG. 3is referred to as an “airflow direction” in which air flows through an air passage53, a left side in the airflow direction is referred to as an “upstream side”, and a right side in the airflow direction is referred to as a “downstream side”.

InFIGS. 2 and 3, the evaporator40includes a refrigerant passage member which has a plurality of branches. The refrigerant passage member is provided as a passage member made of metal such as aluminum. The refrigerant passage member includes a first header41, a second header42, a third header43, and a fourth header44which are positioned in pairs, and a plurality of refrigerant tubes45which couple the headers. The first header41, the second header42, the third header43, and the fourth header44extend in the inflow direction. The refrigerant tubes45extend in the height direction which is perpendicular to the inflow direction.

InFIGS. 2 and 3, the first header41is paired with the second header42. The first header41and the second header42are disposed apart from each other by a predetermined distance in the height direction and parallel to each other in the inflow direction. Also, the third header43is paired with the fourth header44. The third header43and the fourth header44are disposed apart from each other by a predetermined distance in the height direction and parallel to each other in the inflow direction. The first header41and the third header43are disposed on the upper side in the height direction. The second header42and the fourth header44are disposed on the lower side in the height direction.

A plurality of refrigerant tubes45are arrayed at regular intervals between the first header41and the second header42. Each of the refrigerant tubes45communicates with the inside of the first header41and the inside of the second header42at one end thereof. The first header41, the second header42, and the refrigerant tubes45disposed between the first header41and the second header42form a first heat exchange unit48.

A plurality of refrigerant tubes45are arrayed at regular intervals between the third header43and the fourth header44. Each of the refrigerant tubes45communicates with the inside of the third header43and the inside of the fourth header44at the other end thereof. The third header43, the fourth header44, and the refrigerant tubes45disposed between the third header43and the fourth header44form a second heat exchange unit49.

As a result, the evaporator40includes the first heat exchange unit48and the second heat exchange unit49which are disposed in two layers. In the airflow direction, the second heat exchange unit49is disposed at the upstream side, and the first heat exchange unit48is disposed at the downstream side. The refrigerant tubes45are disposed in two rows in the inflow direction so as to be paired in the airflow direction.

A joint as a refrigerant inlet is disposed at an end (the end at the front side in the inflow direction) of the first header41. As illustrated inFIGS. 4 to 6, the inside of the first header41is partitioned into a first section and a second section by a partition plate which is disposed at substantially the center in the length direction (inflow direction) of the first header41. Correspondingly, the refrigerant tubes45are divided into a first group G1corresponding to the first section and a second group G2corresponding to the second section.

The refrigerant is supplied to the first section of the first header41. The refrigerant is distributed to the refrigerant tubes45belonging to the first group G1from the first section. The refrigerant flows into the second header42through the refrigerant tubes45of the first group G1so as to be collected in the second header42. The refrigerant is redistributed to the refrigerant tubes45belonging to the second group G2from the second header42. The refrigerant flows into the second section of the first header41through the refrigerant tubes45of the second group G2. In this manner, a U-shaped flow passage for the refrigerant is formed in the first heat exchange unit48.

A joint as a refrigerant outlet is disposed at an end (the end at the front side in the inflow direction in the present embodiment, but may be an end at the back side) of the third header43. As illustrated inFIGS. 4 to 6, the inside of the third header43is partitioned into a first section and a second section by a partition plate which is disposed at substantially the center in the length direction of the third header43. The first section of the third header43is adjacent to the second section of the first header41. The first section of the third header43communicates with the second section of the first header41. Correspondingly, the refrigerant tubes45are divided into a third group G3corresponding to the first section and a fourth group G4corresponding to the second section.

The refrigerant flows into the first section of the third header43from the second section of the first header41. The refrigerant is distributed to the refrigerant tubes45belonging to the third group G3from the first section. The refrigerant flows into the fourth header44through the refrigerant tubes45of the third group G3so as to be collected in the fourth header44. The refrigerant is redistributed to the refrigerant tubes45belonging to the fourth group G4from the fourth header44. The refrigerant flows into the second section of the third header43through the refrigerant tubes45of the fourth group G4. In this manner, a U-shaped flow passage for the refrigerant is formed in the second heat exchange unit49. The refrigerant inside the second section of the third header43flows out of the refrigerant outlet and flows toward the compressor10.

In the present embodiment, the refrigerant tube45is a multi-hole tube which includes a plurality of refrigerant passages inside thereof. The refrigerant tube45is also called a flat tube. The multi-hole tube can be obtained by an extrusion method or a method of bending and forming a plate. The refrigerant passages extend in the longitudinal direction of the refrigerant tube45, and are open on both ends of the refrigerant tube45. The refrigerant tubes45are arranged in rows. In each of the rows, the refrigerant tubes45are disposed with the principal faces thereof facing each other. As illustrated inFIG. 8, the air passage53for heat exchange with air or a storage area for storing a cold storage material container47(described below) is formed between each adjacent two of the refrigerant tubes45.

The evaporator40includes a fin member for increasing the contact area with air supplied to the vehicle cabin. The fin member is provided as a plurality of fins46each having a corrugated shape. Each of the fins46is disposed in the air passage53which is formed between two adjacent refrigerant tubes45. The fin46is thermally coupled to the two adjacent refrigerant tubes45. The fin46is joined to the two adjacent refrigerant tubes45with a joining material that is excellent in heat transfer. A brazing material can be used as the joining material. The fin46is made of a thin metal plate, such as a thin aluminum plate, which is formed into a wave shape. The fin46includes an air passage called a louver.

The evaporator40further includes a plurality of cold storage material containers47. The cold storage material container47is made of metal such as aluminum. The cold storage material container47has a flat tubular shape. The cold storage material container47forms a chamber for storing a cold storage material50inside thereof by joining two plates having a hollow shape. The cold storage material container47includes wide principal faces at both sides thereof. Further, two principal walls which form the respective two principal faces are parallel to the refrigerant tubes45. The cold storage material container47is disposed between two adjacent refrigerant tubes45.

The cold storage material container47is disposed between the two refrigerant tubes45which are adjacent to each other in the inflow direction. The cold storage material container47is thermally coupled to the two refrigerant tubes45disposed on both sides thereof. The cold storage material container47is joined to the two adjacent refrigerant tubes45with a joining material that is excellent in heat transfer. A brazing material or a resin material such as an adhesive can be used as the joining material. The cold storage material container47is brazed to the refrigerant tubes45. The brazing material is disposed between the cold storage material container47and each of the refrigerant tubes45so as to couple the cold storage material container47and the refrigerant tubes45through a large sectional area. As the brazing material, a material clad with a brazing material may be used, or a brazing material foil may be disposed between the cold storage material container47and each of the refrigerant tubes45. As a result, excellent heat transfer is exhibited between the cold storage material container47and the refrigerant tubes45. The surface of the cold storage material container47may have recesses and projections, and the projections may be joined to the refrigerant tubes45.

InFIGS. 2 and 8, the refrigerant tubes45are arranged at substantially regular intervals. A plurality of spaces are formed between the refrigerant tubes45. The fins46and the cold storage material containers47are arranged in the spaces with a predetermined regularity.FIGS. 2 and 8illustrate a structure in which two fins46(air passages53) and one cold storage material container47are repeatedly arranged in this order. However, an arrangement other than the illustrated arrangement may be employed. Some of the spaces serve as the air passages53. The remaining spaces serve as the storage areas. The fins46are disposed in the respective air passages53. The cold storage material containers47are disposed in the respective storage areas. Each of two refrigerant tubes45that are located on both sides of the cold storage material container47defines the air passage for heat exchange with air at the side opposite to the cold storage material container47. In another point of view, two refrigerant tubes45are disposed between two fins46, and one cold storage material container47is further disposed between the two refrigerant tubes45. It is possible to transfer heat of the refrigerant to the cold storage material50without receiving a heat load of air flowing through the fin46by the cold storage material container47disposed between the two refrigerant tubes45. Thus, the cold storage efficiency is improved.

One cold storage material container47and two refrigerant tubes45located on both sides of the cold storage material container47constitute one cold storage unit. A plurality of cold storage units having the same structure are arranged on the evaporator40. The cold storage units are arranged at regular intervals. Further, the cold storage units are equally arranged right and left. Furthermore, the cold storage units are symmetrically arranged right and left.

As illustrated inFIG. 10, the cold storage material container47is joined to both of the refrigerant tubes45of the first heat exchange unit48and the second heat exchange unit49in the airflow direction. As illustrated inFIG. 8, the cold storage material container47includes an outer shell47a. The outer shell47ais made of a plate material which is formed into a flat tubular shape. An inner fin47bhaving a corrugated shape is stored in the outer shell47a. The inner fin47bis made of a metal plate, such as a thin aluminum plate, which is formed into a wave shape like the fin46. A plurality of tops of the inner fin47bare brazed to the inner faces of principal walls (the walls whose outer surfaces are principal faces joined to the refrigerant tubes45) on both sides in the inflow direction of the outer shell47a. As illustrated inFIGS. 9 and 10, the inner fin47bextends in the longitudinal direction (height direction) of the cold storage material container47. Peaks and valleys of the inner fin47bextend in the airflow direction. With such a structure, the inner fin47bincreases the contact area between the cold storage material50and the cold storage material container47. Details of the shape of the inner fin47bwill be described below.

Hereinbelow, the first header41is also referred to as an inlet side passage which includes an inlet of the refrigerant passage. Similarly, the third header43is also referred to as an outlet side passage which includes an outlet of the refrigerant passage. The first header41and the third header43are disposed in parallel in the airflow direction at the same position in the height direction and collectively referred to as a first header tank51. Similarly, the second header42and the fourth header44are disposed in parallel in the airflow direction at the same position in the height direction and collectively referred to as a second header tank52.

As schematically illustrated inFIGS. 4 to 6, a refrigerant flowing into the first section of the first header41flows into the first section of the second header42through the refrigerant tubes45of the first group G1(first turn). The refrigerant flowing into the first section of the second header42flows into the second section of the second header42. The refrigerant flowing into the second section of the second header42flows into the second section of the first header41through the refrigerant tubes45of the second group G2(second turn). The second section of the first header41and the second section of the third header43communicate with each other. Thus, the refrigerant flowing into the second section of the first header41flows into the second section of the third header43. The refrigerant flowing into the second section of the third header43flows into the second section of the fourth header44through the refrigerant tubes45of the third group G3(third turn). The refrigerant flowing into the second section of the fourth header44flows into the first section of the fourth header44. The refrigerant flowing into the first section of the fourth header44flows into the first section of the third header43through the refrigerant tubes45of the fourth group G4(fourth turn). The refrigerant flowing into the first section of the third header43flows out to the outside. That is, the evaporator40of the present embodiment is configured to include a so-called four-turn type refrigerant passage.

As illustrated inFIG. 1, in the refrigerating cycle apparatus1, the compressor10for compressing and ejecting the refrigerant is typically present on the downstream side in the flow of the refrigerant relative to the evaporator40. A return of the refrigerant in a liquid state to the compressor10causes a failure. Thus, it is typically necessary to completely evaporate the refrigerant at an outlet of the evaporator40. Accordingly, the refrigerant forms a single gas layer near the outlet of the refrigerant passage, and the pressure thereof exceeds the saturated vapor pressure. As a result, there is a part where a refrigerant temperature rapidly transitions to a high temperature, that is, an overheated area S.FIG. 7illustrates an example of the characteristics of the refrigerant temperature in the four-turn type refrigerant passage. The horizontal axis ofFIG. 7represents the position in the refrigerant passage. The left side (an origin point side) of the horizontal axis corresponds to the inlet, and the right side thereof corresponds to the outlet. The vertical axis ofFIG. 7represents the refrigerant temperature in each passage position. As illustrated inFIG. 7, the refrigerant temperature decreases after the refrigerant is introduced into the refrigerant passage. However, the refrigerant temperature rapidly transitions to a high temperature at a substantially intermediate position in the fourth turn (that is, the fourth group G4), and the overheated area S is formed in a part thereafter. For example, as illustrated inFIG. 5, the overheated area S is formed in a substantially half area on the upper side in the height direction in the refrigerant tubes45of the fourth group G4.

As illustrated inFIG. 10, the cold storage material container47is joined to both of the refrigerant tubes45of the first heat exchange unit48and the second heat exchange unit49in the airflow direction. Thus, in a conventional cold storage material container47, cold storage is interrupted at the refrigerant tubes45of the fourth group G4, due to the influence of the overheated area S, that is, cold storage is interrupted only in the cold storage material50in a part that is in contact with the refrigerant tubes45on the upstream side in the airflow direction. Thus, there is a difference in cooling of the cold storage material50inside the cold storage material container47between the upstream side and the downstream side in the airflow direction. Accordingly, there may be a difference in a blowout temperature between the back side and the front side in the inflow direction (that is, between an area that does not include the overheated area S and an area that includes the overheated area S) during cold release.

In view of the above issue, in the present embodiment, as illustrated inFIGS. 9 and 10, the inner fin47bhas a shape that is not joined to the cold storage material container47in the overheated area S of the refrigerant. In other words, in the cold storage material container47which is joined to the refrigerant tube45having the overheated area S, the inner fin47bis not joined to the inner wall surface of the outer shell47aof the cold storage material container47in a part that is in contact with the overheated area S of the refrigerant tube45and is joined to the inner wall surface in a part that is in contact with an area other than the overheated area S of the refrigerant tube45. InFIG. 10, a part where the tops of the inner fin47bare joined to the cold storage material container47is indicated by solid lines, and a part where the tops of the inner fin47bare not joined to the cold storage material container47is indicated by dotted lines.

Further, the above structure can be reworded as follows. In the evaporator40, the plurality of refrigerant tubes45include at least two refrigerant tubes45disposed in the airflow direction of air in the air passages53. The cold storage material container47is joined to the at least two refrigerant tubes45disposed in the airflow direction. In this case, the joined part may have recesses and projections, and the projections may be joined to the refrigerant tubes45. The inner fin47boverlaps the at least two refrigerant tubes45when viewed in an array direction of the refrigerant tubes45and the cold storage material container47(inflow direction). The cold storage material container47which is joined to the at least two refrigerant tubes45including the refrigerant tube45having the overheated area S includes a part that is in contact with the overheated area S of the refrigerant tube45. When viewed in the airflow direction, the inner fin47bis not joined to the inner wall of the cold storage material container47in an area that overlaps the part, and is joined to the inner wall of the cold storage material container47in the other area.

With the above structure, the inner fin47bis not joined to the cold storage material container47, that is, the refrigerant tubes45in the overheated area S. Thus, heat from the overheated refrigerant is less likely to be transferred to the inside of the cold storage material50. Further, the inner fin47bitself is disposed (is floating) inside the cold storage material container47also in the overheated area S. Thus, cold of the refrigerant in a non-overheated area is transferred also to the cold storage material50in the overheated area through the inner fin47b. In this manner, it is possible to reduce the transfer of heat in the overheated area to the cold storage material50present in the overheated area S and also possible to transfer cold in the non-overheated area to the cold storage material50present in the overheated area S. Thus, even when there is the overheated area S in the refrigerant passage, it is possible to cool the cold storage material50inside the cold storage material container47in an excellent manner. Accordingly, it is possible to eliminate such an inconvenience that the cold storage material50inside the cold storage material container47in the overheated area S is not cooled and there is a temperature distribution inside the evaporator (evaporator40) during cold release, or, in the first place, cold storage cannot be performed due to the influence of the overheated area.

That is, in the first embodiment, the inner fin47bis not joined to the cold storage material container47in the overheated area S. Accordingly, the inner fin47bfunctions as a “heat transfer suppressor” which suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S which is formed by evaporation of the refrigerant near the outlet of the refrigerant passage. Further, the inner fin47bhaving such a structure makes it possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S and avoid a situation in which the cold storage material50is less cooled due to the influence of the overheated area S where the refrigerant temperature becomes high. As a result, the evaporator40as the cold storage heat exchanger of the first embodiment is capable of ensuring the cold storage performance by reducing the influence of the overheated area S even when there is the overheated area S.

Modifications of First Embodiment

A modification of the first embodiment will be described with reference toFIGS. 11 to 20. In the first embodiment, in the evaporator40, the inner fin47bis not joined to the inner wall surface of the outer shell47aof the cold storage material container47in the part that is in contact with the overheated area S of the refrigerant tube45and is joined to the inner wall surface in the part that is in contact with the area other than the overheated area S of the refrigerant tube45. However, there may be employed another structure that makes a heat transfer amount from the refrigerant tube45to the cold storage material50through the inner fin47bin the overheated area S relatively smaller than a heat transfer amount in an area other than the overheated area S. In other words, it may only be required to make the heat transfer performance of the inner fin47bin the overheated area S relatively lower than that in the other part. For example, as illustrated inFIG. 11, in an evaporator401, an inner fin471bmay be joined to an inner wall surface of an outer shell471aof a cold storage material container471with a relatively low joining ratio in a part that is in contact with the overheated area S of the refrigerant tube45and joined to the inner wall surface with a relatively high joining ratio in a part that is in contact with an area other than the overheated area S of the refrigerant tube45. The “relatively low joining ratio” indicates that the number of peaks and valleys of the inner fin471bthat are joined to the inner wall surface of the outer shell471ais relatively small. The “relatively high joining ratio” indicates that the number of peaks and valleys of the inner fin471bthat are joined to the inner wall surface of the outer shell471ais relatively large. The evaporator401is capable of suppressing heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S by making the heat transfer amount through the inner fin471bin the overheated area S relatively small or making the joining ratio between the inner fin471band the cold storage material container471relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator40of the first embodiment.

In the first embodiment, in the evaporator40, the corrugated shape of the inner fin47bis continuous in the longitudinal direction (height direction) of the cold storage material container47, that is, the peaks and the valleys of the inner fin47bextend in the airflow direction. However, the corrugated shape of the inner fin47bmay be continuous in a direction different from the above direction. For example, as illustrated inFIG. 12, in an evaporator402, the corrugated shape of an inner fin472bmay be continuous in the short direction (airflow direction) of a cold storage material container472, that is, peaks and valleys of the inner fin472bmay extend in the height direction. In this case, the peaks and valleys of the inner fin472bare not joined to an inner wall surface of an outer shell472aof the cold storage material container472in a part that is in contact with the overheated area S of the refrigerant tube45in the height direction and are joined to the inner wall surface in a part that is in contact with an area other than the overheated area S of the refrigerant tube45. Accordingly, the evaporator402is capable of suppressing heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S. As a result, it is possible to obtain an effect similar to the effect of the evaporator40of the first embodiment.

In the first embodiment, the four-turn type has been described as an example of the structure of the refrigerant passage inside the evaporator40. However, the present disclosure is not limited thereto. For example, as illustrated inFIGS. 13 to 15, there may be no section inside a first header41A, a second header42A, a third header43A, and a fourth header44A. In a cold storage heat exchanger40A illustrated inFIGS. 13 to 15, a refrigerant flowing into the first header41A flows into the second header42A through the refrigerant tubes45of the first heat exchange unit48(first turn). The second header42A and the fourth header44A communicate with each other. Thus, the refrigerant flowing into the second header42A flows into the fourth header44A. The refrigerant flowing into the fourth header44A flows into the third header43A through the refrigerant tubes45of the second heat exchange unit49(second turn). The refrigerant flowing into the third header43A flows out to the outside. That is, the cold storage heat exchanger40A is configured to include a so-called two-turn type refrigerant passage.

FIG. 16illustrates an example of the characteristics of a refrigerant temperature in the two-turn type refrigerant passage. As illustrated inFIG. 16, the refrigerant temperature decreases after the refrigerant is introduced into the refrigerant passage. However, the refrigerant temperature rapidly transitions to a high temperature at a position in the second half of the second turn, and an overheated area S is formed in the following part. For example, as illustrated inFIG. 14, the overheated area S is formed in an area on the upper side in the height direction in refrigerant tubes45of the second heat exchange unit49.

The inner fin47bof the first embodiment can also be used in a cold storage heat exchanger that forms the flow of a refrigerant as formed in the cold storage heat exchanger40A and can function as the heat transfer suppressor.

In the cold storage heat exchange40A, there is no section inside the first header41A, the second header42A, the third header43A, and the fourth header44A. However, there may be more sections inside the headers.

In a cold storage heat exchanger40B illustrated inFIG. 17, the inside of each of a first header41B, a second header42B, a third header43B, and a fourth header44B is partitioned into three sections.

A refrigerant flowing into a first section of the first header41B flows into a first section of the second header42B through refrigerant tubes45(first turn). The refrigerant flowing into the first section of the second header42B flows into a second section of the second header42B. The refrigerant flowing into the second section of the second header42B flows into a second section of the first header41B through refrigerant tubes45(second turn).

The refrigerant flowing into the second section of the first header41B flows into a third section of the first header41B. The refrigerant flowing into the third section of the first header41B flows into a third section of the second header42B through refrigerant tubes45(third turn). The third section of the second header42B and a third section of the fourth header44B communicate with each other. Thus, the refrigerant flowing into the third section of the second header42B flows into the third section of the fourth header44B. The refrigerant flowing into the third section of the fourth header44B flows into a third section of the third header43B through refrigerant tubes45(fourth turn).

The refrigerant flowing into the third section of the third header43B flows into a second section of the third header43B. The refrigerant flowing into the second section of the third header43B flows into a second section of the fourth header44B through refrigerant tubes45(fifth turn). The refrigerant flowing into the second section of the fourth header44B flows into a first section of the fourth header44B. The refrigerant flowing into the first section of the fourth header44B flows into a first section of the third header43B through refrigerant tubes45(sixth turn). The refrigerant flowing into the first section of the third header43B flows out to the outside. That is, the cold storage heat exchanger40B is configured to include a so-called six-turn type refrigerant passage.

The inner fin47bof the first embodiment can also be used in a cold storage heat exchanger that forms the flow of a refrigerant as formed in the cold storage heat exchanger40B and can function as the heat transfer suppressor.

In the cold storage heat exchangers40,40A,40B, the inlet and the outlet for the refrigerant are formed on the first headers41,41A,41B and the third headers43,43A,43B which are disposed on the upper side in the gravity direction (height direction). The inlet and the outlet for the refrigerant are not limited to the above form. The cold storage heat exchangers40,40A,40B may be configured upside down.

In a cold storage heat exchanger40R illustrated inFIG. 18, a first header41R and a third header43R are disposed on the lower side in the gravity direction (height direction), and a second header42R and a fourth header44R are disposed on the upper side in the gravity direction.

A refrigerant flowing into a first section of the first header41R flows into a first section of the second header42R through refrigerant tubes45(first turn). The refrigerant flowing into the first section of the second header42R flows into a second section of the second header42R. The refrigerant flowing into the second section of the second header42R flows into a second section of the first header41R through refrigerant tubes45(second turn).

The second section of the first header41R and a second section of the third header43R communicate with each other. Thus, the refrigerant flowing into the second section of the first header41R flows into the second section of the third header43R. The refrigerant flowing into the second section of the third header43R flows into a second section of the fourth header44R through refrigerant tubes45(third turn).

The refrigerant flowing into the second section of the fourth header44R flows into a first section of the fourth header44R. The refrigerant flowing into the first section of the fourth header44R flows into a first section of the third header43R through the refrigerant tubes45(fourth turn). The refrigerant flowing into the first section of the third header43R flows out to the outside. That is, the cold storage heat exchanger40R is configured to include a so-called four-turn type refrigerant passage in which the arrangement of the cold storage heat exchanger40is reversed in the height direction.

A cold storage heat exchanger40RA illustrated inFIG. 19is upside down of the cold storage heat exchanger40A illustrated inFIG. 13. The cold storage heat exchanger40RA includes a so-called two-turn type refrigerant passage. A first header41RA and a third header43RA are disposed on the lower side in the gravity direction (height direction). A second header42RA and a fourth header44RA are disposed on the upper side in the gravity direction.

A cold storage heat exchanger40RB illustrated inFIG. 20is upside down of the cold storage heat exchanger40B illustrated inFIG. 17. The cold storage heat exchanger40RB includes a so-called six-turn type refrigerant passage. A first header41RB and a third header43RB are disposed on the lower side in the gravity direction (height direction). A second header42RB and a fourth header44RB are disposed on the upper side in the gravity direction.

Second Embodiment

A second embodiment will be described with reference toFIGS. 21 to 23. An evaporator140of the second embodiment differs from the evaporator40of the first embodiment in the structure of a heat transfer suppressor which suppresses heat transfer from a refrigerant tube45to a cold storage material50in an overheated area S. Specifically, as illustrated inFIGS. 21 and 22, the shape of a cold storage material container147has a structure that is not joined to the refrigerant tube45in the overheated area S of a refrigerant, and the cold storage material container147having the above structure functions as the heat transfer suppressor. Further, the evaporator140of the second embodiment differs from the evaporator40of the first embodiment also in that no inner fin is disposed inside the cold storage material container147.

In other words, the cold storage material container147which is joined to the refrigerant tube45having the overheated area S is separated from the refrigerant tube45without being joined to the refrigerant tube45in a part (area147c) that is in contact with the overheated area S of the refrigerant tube45and joined to the refrigerant tube45in a part (outer shell147a) that is in contact with an area other than the overheated area S of the refrigerant tube45.FIGS. 21 and 22illustrate, as an example of such a structure, a shape in which the surface of the area147cwhich overlaps the overheated area S in the outer shell147aof the cold storage material container147is recessed in a direction separating from the refrigerant tube45.

Further, the structure can be reworded as follows. In the evaporator140, a plurality of refrigerant tubes45include at least two refrigerant tubes45disposed in the airflow direction of air in an air passage53. The cold storage material container147is joined to the at least two refrigerant tubes45which are disposed in the airflow direction. The cold storage material container147which is joined to the at least two refrigerant tubes45including the refrigerant tube45having the overheated area S is separated from the refrigerant tubes45without being joined to the refrigerant tubes45in the area147cwhich includes a part that is in contact with the overheated area S of the refrigerant tube45and overlaps the part when viewed in the airflow direction, and the cold storage material container147is joined to the refrigerant tubes45in an area147aother than the area147c.

With the above structure, the cold storage material container147is not joined to the refrigerant tubes45in the overheated area S. Thus, heat from the overheated refrigerant is less likely to be transferred to the inside of the cold storage material50. Further, the cold storage material container147itself is in contact with a non-overheated area. Thus, cold of the refrigerant in the non-overheated area is transferred also to the cold storage material50in the overheated area S. Accordingly, the evaporator140of the second embodiment is capable of achieving an effect similar to the effect of the evaporator40of the first embodiment.

The shape of the cold storage material container147of the second embodiment is not limited to the above shape and may have another structure that makes a heat transfer amount from the refrigerant tube45to the cold storage material50through the cold storage material container147in the overheated area S relatively smaller than a heat transfer amount in an area other than the overheated area S. In other words, it may only be required to make the heat transfer performance of the cold storage material container147in the overheated area S relatively lower than that in the other part. For example, as illustrated inFIG. 23, in an evaporator1401, a cold storage material container1471is jointed to the refrigerant tube45with a relatively low joining ratio in a part (area1471c) that is in contact with the overheated area S of the refrigerant tube45and joined to the refrigerant tube45with a relatively high joining ratio in a part (outer shell1471a) that is in contact with an area other than the overheated area S of the refrigerant tube45. The “relatively low joining ratio” indicates that the ratio of a part joined to the refrigerant tube45in the outer surface of the cold storage material container1471is relatively small. The “relatively high joining ratio” indicates that the ratio of a part joined to the refrigerant tube45in the outer surface of the cold storage material container1471is relatively large. The evaporator1401is capable of suppressing heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S by making the heat transfer amount of the cold storage material container1471in the overheated area S relatively small or making the joining ratio between the cold storage material container1471and the refrigerant tube45in the overheated area relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator40of the first embodiment.

Third Embodiment

A third embodiment will be described with reference toFIGS. 24 to 26. An evaporator240of the third embodiment differs from the evaporator40of the first embodiment in the structure of a heat transfer suppressor which suppresses heat transfer from a refrigerant tube45to a cold storage material50in an overheated area S. Specifically, as illustrated inFIGS. 24 and 25, the shape of a cold storage material container247has a structure that is not joined to the refrigerant tube45in the overheated area S of the refrigerant, and the cold storage material container247having the structure functions as the heat transfer suppressor. Further, the evaporator240of the third embodiment differs from the evaporator40of the first embodiment also in that an inner fin247bwhich is disposed inside the cold storage material container247is joined to an inner wall surface of an outer shell247aover the entire area in the longitudinal direction.

In other words, the inner fin247bextends in the longitudinal direction (height direction) inside the cold storage material container247, and is joined to an inner wall of the cold storage material container247. The cold storage material container247which is joined to the refrigerant tube45having the overheated area S is separated from the refrigerant tube45without being joined to the refrigerant tube45in a part (area247c) that is in contact with the overheated area S of the refrigerant tube45and joined to the refrigerant tube45in a part (outer shell147a) that is in contact with an area other than the overheated area S of the refrigerant tube45.

Further, the above structure can be reworded as follows. In the evaporator240, a plurality of refrigerant tubes45include at least two refrigerant tubes45disposed in the airflow direction of air in an air passage53. The cold storage material container247is joined to the at least two refrigerant tubes45which are disposed in the airflow direction. The inner fin247boverlaps the at least two refrigerant tubes45when viewed in an array direction (inflow direction) of the refrigerant tubes45and the cold storage material container247. The cold storage material container247which is joined to the at least two refrigerant tubes45including the refrigerant tube45having the overheated area S is separated from the refrigerant tubes45without being joined to the refrigerant tubes45in the area247cwhich includes a part that is in contact with the overheated area S of the refrigerant tube45and overlaps the part when viewed in the airflow direction and joined to the refrigerant tubes45in an area247aother than the area247c.

With the above structure, the cold storage material container247is not joined to the refrigerant tubes45in the overheated area S. Further, the inner fin247bwhich is joined to the inside of the cold storage material container247is also not joined to the refrigerant tubes45. Thus, heat from the overheated refrigerant is less likely to be transferred to the inside of the cold storage material50. The inner fin247bitself is disposed also inside the cold storage material container47in the overheated area S. Thus, cold of the refrigerant in a non-overheated area is transferred also to the cold storage material50in the overheated area S through the inner fin247b. Further, the cold storage material container247itself is in contact with the non-overheated area. Thus, cold of the refrigerant in the non-overheated area is transferred also to the cold storage material50in the overheated area S. Accordingly, the evaporator240of the third embodiment is capable of achieving an effect similar to the effect of the evaporator40of the first embodiment.

The evaporator240of the third embodiment may also have a structure in which the inner fin247bis not joined to the inner wall surface of the outer shell247aof the cold storage material container247in a part that is in contact with the overheated area S of the refrigerant tube45similarly to the first embodiment. With the above structure, since the inner fin247bis not joined to the cold storage material container247, that is, the refrigerant tube45in the overheated area S, heat from the overheated refrigerant is further less likely to be transferred to the inside of the cold storage material50.

The shape of the cold storage material container247of the third embodiment is not limited to the above shape and may have another structure that makes a heat transfer amount from the refrigerant tube45to the cold storage material50through the cold storage material container247in the overheated area S relatively smaller than a heat transfer amount in an area other than the overheated area S. In other words, it may only be required to make the heat transfer performance of the cold storage material container247in the overheated area S relatively lower than that in the other part. For example, similarly to the structure described in the second embodiment with reference toFIG. 23, as illustrated inFIG. 26, in an evaporator2401, a cold storage material container2471may be jointed to the refrigerant tube45with a relatively low joining ratio in a part (area2471c) that is in contact with the overheated area S of the refrigerant tube45and joined to the refrigerant tube45with a relatively high joining ratio in a part (outer shell2471a) that is in contact with an area other than the overheated area S of the refrigerant tube45. The evaporator2401is capable of suppressing heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S by making the heat transfer amount of the cold storage material container2471in the overheated area S relatively small or making the joining ratio between the cold storage material container2471and the refrigerant tube45in the overheated area S relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator40of the first embodiment.

Further, when there is applied a structure that suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S by a joining structure between the inner fin2471band the cold storage material container2471similarly to the first embodiment, a structure similar to the structure described in the first embodiment with reference toFIG. 11can be applied. Specifically, as illustrated inFIG. 26, in the evaporator2401, the inner fin2471bmay be joined to the inner wall surface of the outer shell2471aof the cold storage material container2471with a relatively low joining ratio in a part that is in contact with the overheated area S of the refrigerant tube45and joined to the inner wall surface with a relatively high joining ratio in a part that is in contact with an area other than the overheated area S of the refrigerant tube45. The evaporator2401is capable of suppressing heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S also by making the joining ratio between the inner fin2471band the cold storage material container2471relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator40of the first embodiment.

Further, similarly to the structure described in the first embodiment with reference toFIG. 12, in the evaporator240, the corrugated shape of the inner fin247bmay be continuous in the short direction (airflow direction) of the cold storage material container247, that is, peaks and valleys of the inner fin247bmay extend in the height direction. Also with the above structure, the evaporator240is capable of suppressing heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S. As a result, it is possible to obtain an effect similar to the effect of the evaporator40of the first embodiment.

Fourth Embodiment

A fourth embodiment will be described with reference toFIGS. 27 and 28. In an evaporator340of the fourth embodiment, the shape of an inner fin347bas the heat transfer suppressor differs from the shape of the inner fin47bin the evaporator40of the first embodiment. Specifically, as illustrated inFIGS. 27 and 28, when refrigerant tubes45are disposed on the upstream side and the downstream side in the airflow direction, an overheated area S is typically formed on the upstream side. Thus, the fourth embodiment differs from the first embodiment in that the inner fin347bis not joined to a cold storage material container347only on the upstream side.

In other words, in the evaporator340, a plurality of refrigerant tube45include at least two refrigerant tubes45disposed in the airflow direction of air in an air passage53. The cold storage material container347is joined to the at least two refrigerant tubes which are disposed in the airflow direction. The inner fin347boverlaps the at least two refrigerant tubes45when viewed in an array direction (inflow direction) of the refrigerant tubes45and the cold storage material container347. In the cold storage material container347which is joined to the at least two refrigerant tubes45including the refrigerant tube45having the overheated area S, the inner fin347bis joined to the inner wall of the cold storage material container347over the entire area in the longitudinal direction in an area overlapping the refrigerant tube45having no overheated area S. Further, in an area overlapping the refrigerant tube45having the overheated area S, the inner fin347bis not joined to the inner wall of the cold storage material container347in a part that is in contact with the overheated area S of the refrigerant tube45and joined to the inner wall of the cold storage material container347in the other part.

With the above structure, the evaporator340achieves an effect similar to the effect of the first embodiment. Further, since the inner fin347bis in contact with the refrigerant tube45in a non-overheated area on the downstream side, cold can be transferred from the upstream side to the downstream side. Thus, it is possible to further suppress heat transfer from the refrigerant tube45to the cold storage material50.

Further, the various modifications described in the first embodiment can be applied to the evaporator of340of the fourth embodiment.

Fifth Embodiment

A fifth embodiment will be described with reference toFIGS. 29 and 30. In an evaporator440of the fifth embodiment, the shape of a cold storage material container447as the heat transfer suppressor differs from the shape of the cold storage material container147in the evaporator140of the second embodiment. Specifically, as illustrated inFIGS. 29 and 30, when refrigerant tubes45are disposed on the upstream side and the downstream side in the airflow direction, an overheated area S is typically formed on the upstream side. Thus, the fifth embodiment differs from the second embodiment in that the cold storage material container447is not joined to the refrigerant tubes45only on the upstream side.

In other words, in the evaporator440, a plurality of refrigerant tubes45include at least two refrigerant tubes45disposed in the airflow direction of air in an air passage53. The cold storage material container447is joined to the at least two refrigerant tubes45which are disposed in the airflow direction. The cold storage material container447which is joined to the at least two refrigerant tubes45including the refrigerant tube45having the overheated area S is joined to the refrigerant tubes45over the entire area in the extending direction (height direction) in an area overlapping the refrigerant tube45having no overheated area S. Further, in an area overlapping the refrigerant tube45having the overheated area S, the cold storage material container447is separated from the refrigerant tubes45without being joined to the refrigerant tubes45in a part (area447c) that is in contact with the overheated area S of the refrigerant tube45and joined to the refrigerant tube45in a part447aother than the area447c.

With the above structure, the evaporator440of the fifth embodiment achieves an effect similar to the effect of the second embodiment. Further, since the cold storage material container447is in contact with the refrigerant tube45in a non-overheated area on the downstream side, cold can be transferred from the upstream side to the downstream side. Thus, it is possible to further suppress heat transfer from the refrigerant tube45to the cold storage material50. Further, the capacity of the cold storage material container447can be increased compared to that of the second embodiment. Thus, it is possible to store a larger amount of cold storage material50.

Further, the various modifications described in the second embodiment can be applied to the evaporator440of the fifth embodiment.

Sixth Embodiment

A sixth embodiment will be described with reference toFIGS. 31 and 32. In an evaporator540of the sixth embodiment, the shape of a cold storage material container547as the heat transfer suppressor differs from the shape of the cold storage material container247in the evaporator240of the third embodiment. Specifically, as illustrated inFIGS. 31 and 32, when refrigerant tubes45are disposed on the upstream side and the downstream side in the airflow direction, an overheated area S is typically formed on the upstream side. Thus, the sixth embodiment differs from the third embodiment in that the cold storage material container547is not joined to the refrigerant tubes45only on the upstream side.

In other words, in the evaporator540, a plurality of refrigerant tubes45include at least two refrigerant tubes45disposed in the airflow direction of air in an air passage53. The cold storage material container547is joined to the at least two refrigerant tubes45which are disposed in the airflow direction. An inner fin547boverlaps the at least two refrigerant tubes45when viewed in an array direction (inflow direction) of the refrigerant tubes45and the cold storage material container547. The cold storage material container547which is joined to the at least two refrigerant tubes45including the refrigerant tube45having the overheated area S is joined to the refrigerant tube45over the entire area in the extending direction (height direction) in an area overlapping the refrigerant tube45having no overheated area S. Further, in an area overlapping the refrigerant tube45having the overheated area S, the cold storage material container547is separated from the refrigerant tube45without being joined to the refrigerant tube45in a part (area547c) that is in contact with the overheated area S of the refrigerant tube45and joined to the refrigerant tube45in a part547aother than the area547c.

With the above structure, the evaporator540of the sixth embodiment achieves an effect similar to the effect of the third embodiment. Further, since the cold storage material container547and the inner fin547bare in contact with the refrigerant tube45in a non-overheated area on the downstream side, cold can be transferred from the upstream side to the downstream side. Thus, it is possible to further suppress heat transfer from the refrigerant tube45to the cold storage material50. Further, the capacity of the cold storage material container547can be increased compared to that of the third embodiment. Thus, it is possible to store a larger amount of cold storage material50.

Further, the various modifications described in the third embodiment can be applied to the evaporator540of the sixth embodiment.

Seventh Embodiment

A seventh embodiment will be described with reference toFIGS. 33 to 38. In the seventh embodiment and embodiments thereafter, an overheated area S1as a subject differs from the overheated area S of the first to sixth embodiments. An evaporator1040(cold storage heat exchanger) according to the seventh embodiment suppresses heat transfer from a refrigerant tube45to a cold storage material50in the overheated area S1which is formed due to flow rate variations in a refrigerant passage when the flow rate of a refrigerant is low.

First, an issue in an evaporator2040which includes a conventional two-turn type refrigerant passage will be described as a comparative example with reference toFIGS. 36 to 38.

In the evaporator2040, a refrigerant flowing into a first header2041flows into a second header2042through refrigerant tubes45of a first heat exchange unit48(first turn). The second header2042and a fourth header2044communicate with each other. Thus, the refrigerant flowing into the second header2042flows into the fourth header2044. The refrigerant flowing into the fourth header2044flows into a third header2043through refrigerant tubes45of a second heat exchange unit49(second turn). The refrigerant flowing into the third header2043flows out to the outside.

In the evaporator2040having such a structure, when the flow rate of the refrigerant is low, the refrigerant is likely to flow only to refrigerant tubes45on the front side in the inflow direction near an inlet of the refrigerant passage and less likely to be supplied to refrigerant tubes45on the back side in the inflow direction. Thus, when the flow rate of the refrigerant inside the refrigerant passage is low, there is the overheated area S1in an area on the back side in the inflow direction. An overheated area S2(second overheated area) illustrated inFIG. 37is an overheated area which is formed near an outlet and a subject in the first to sixth embodiments.

The evaporator1040of the seventh embodiment is characterized in the structure of the refrigerant passage in order to reduce the influence of the overheated area S1as described above and ensure a cold storage performance of the cold storage material50. The evaporator1040is similar to the evaporator1040of the first embodiment in the basic structure, but differs from the evaporator1040of the first embodiment in the structure of the refrigerant passage, more specifically, in sections inside a first header1041, a second header1042, a third header1043, and a fourth header1044and a mutual communication relationship therebetween.

As illustrated inFIGS. 33 to 35, a first section and a second section communicate with each other inside the first header1041differently from the first header41of the first embodiment. Thus, a refrigerant supplied to the first header1041is distributed to a plurality of refrigerant tubes45belonging to a first group G1and a second group G2. The refrigerant flows into a first section of the second header1042through the refrigerant tubes45of the first group G1and flows into a second section of the second header1042through the refrigerant tubes45of the second group G2.

The second header1042differs from the second header42of the first embodiment in that the first section and the second section are uncommunicably sealed. Similarly, the fourth header1044differs from the fourth header44of the first embodiment in that a first section and a second section are uncommunicably sealed. The first section of the second header42which is located on the front side in the inflow direction and the downstream side in the airflow direction communicates with the first section of the fourth header1044which is located on the back side in the inflow direction and the upstream side in the airflow direction. The second section of the second header42which is located on the back side in the inflow direction and the downstream side in the airflow direction communicates with the second section of the fourth header1044which is located on the front side in the inflow direction and the upstream side in the airflow direction. Correspondingly, the refrigerant flows into the first section of the fourth header1044from the first section of the second header1042and flows into the second section of the fourth header1044from the second section of the second header1042.

A first section and a second section communicate with each other inside the third header1043differently from the third header43of the first embodiment. The refrigerant flowing into the first section of the fourth header1044is distributed to a plurality of refrigerant tubes45belonging to a third group G3. The refrigerant flowing into the second section of the fourth header1044is distributed to a plurality of refrigerant tubes45belonging to a fourth group G4. The refrigerant flows into the third header1043through the refrigerant tubes45of the third group G3and the fourth group G4so as to be collected therein. The refrigerant inside the third header1043flows out of the refrigerant outlet and flows toward the compressor10.

In this manner, in the evaporator1040of the seventh embodiment, the refrigerant passage has a structure that changes the position in the inflow direction of the refrigerant introduced from the first header1041on the upper side in the height direction in a second header tank52on the lower side in the height direction. That is, the position of the refrigerant introduced from the front side in the inflow direction through the refrigerant tubes45of the first group G1is changed to the back side in the inflow direction. Further, the position of the refrigerant introduced from the back side in the inflow direction through the refrigerant tubes45of the second group G2is changed to the front side in the inflow direction. As illustrated inFIGS. 33 and 35, a schematic shape of the refrigerant passage inside the second header tank52is an X shape when viewed in the height direction. Further, a schematic shape of the refrigerant passage inside the evaporator1040is a crossed shape of two two-turn type refrigerant passages. The structure of the refrigerant passage of the seventh embodiment is referred to as a “flow change type” for convenience.

The structure of the flow change type refrigerant passage of the seventh embodiment can be described as follows. The evaporator1040includes a first header tank51which is formed in such a manner that refrigerant tubes45communicate with the first header tank51at one end side thereof and the longitudinal direction of the first header tank51is aligned with the array direction (inflow direction) of the refrigerant tubes45and the cold storage material container47and the second header tank52which is formed in such a manner that the refrigerant tubes45communicate with the second header tank52at the other end side thereof and the longitudinal direction of the second header tank52is aligned with the inflow direction. The refrigerant tubes45are arranged in two rows so as to be paired in the airflow direction of air in the air passage53. The inside of the first header tank51is divided into the first header1041and the third header1043. The first header1041is an inlet side passage which communicates with some of the refrigerant tubes45disposed on the downstream side in the airflow direction and includes an inlet of the refrigerant passage on one end in the longitudinal direction thereof. The third header1043is an outlet side passage which communicates with some of the refrigerant tubes45disposed on the upstream side in the airflow direction and includes an outlet of the refrigerant passage on one end (or the other end) in the longitudinal direction thereof.

The refrigerant tubes45are divided into the first group G1, the second group G2, the third group G3, and the fourth group G4. The refrigerant tubes45of the first group G1communicate with the first header1041as the inlet side passage, and are disposed on one end side in the longitudinal direction (the front side in the inflow direction). The refrigerant tubes45of the second group G2communicate with the first header1041as the inlet side passage, and are disposed on the other end side in the longitudinal direction (the back side in the inflow direction). The refrigerant tubes45of the third group G3communicate with the third header1043as the outlet side passage, and are disposed on the other end side in the longitudinal direction. The refrigerant tubes45of the fourth group G4communicate with the third header1043as the outlet side passage, and are disposed on the one end side in the longitudinal direction.

The second header tank52is configured to allow communication between the first group G1and the third group G3and communication between the second group G2and the fourth group G4and change the position of a refrigerant introduced to the front side in the inflow direction from the first header1041and the position of a refrigerant introduced to the back side in the inflow direction from the first header1041to the back side and the front side, respectively, so as to be led to the third header1043. The overheated area S1is formed in the second group G2and the fourth group G4of the refrigerant tubes45due to flow rate variations in the refrigerant passage when the flow rate of the refrigerant is low. With the above structure of the refrigerant passage, as illustrated inFIG. 35, it is possible to achieve a structure in which a single cold storage material container47is joined to both of the second group G2having the overheated area S1and the third group G3having no overheated area S1. Similarly, it is possible to achieve a structure in which a single cold storage material container47is joined to both of the first group G1having no overheated area S1and the fourth group G4having the overheated area S1.

With the structure of the flow change type refrigerant passage as described above, even in a condition in which the refrigerant introduced into the first header1041is less likely to flow into the back side in the inflow direction, for example, when the flow rate of the refrigerant is low, it is possible to provide the flow of the refrigerant with a relatively high flow rate over the entire area in the inflow direction through the refrigerant tubes45of the first group G1and the third group G3. That is, it is possible to flow the refrigerant to the back side in the inflow direction in an excellent manner even when the flow rate of the refrigerant is low. A single cold storage material container47is jointed to two refrigerant tubes45which are disposed in parallel in the airflow direction. The refrigerant flows through one of the two refrigerant tubes45with a relatively high flow rate. Accordingly, even when the overheated area S1is formed on the other one of the two refrigerant tubes45to which the cold storage material container47is joined, cold in a non-overheated area can be transferred to the cold storage material50in the overheated area S1. Thus, it is possible to cool the cold storage material50inside the cold storage material container47in an excellent manner.

That is, the seventh embodiment is characterized in a refrigerant passage structure1045in which a single cold storage material container47is joined to both of the refrigerant tube45having the overheated area S1and the refrigerant tube45having no overheated area by changing the position in the inflow direction of the refrigerant in the second header tank52by the flow change type refrigerant passage. The refrigerant passage structure1045functions as a “heat transfer suppressor” which suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1which is formed due to flow rate variations in the refrigerant passage when the flow rate of the refrigerant is low. Further, the refrigerant passage structure1045as described above makes it possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1and avoid a situation in which the cold storage material50is less cooled due to the influence of the overheated area S1where the refrigerant temperature becomes high. As a result, the evaporator1040as the cold storage heat exchanger of the seventh embodiment is capable of ensuring the cold storage performance by reducing the influence of the overheated area S1even when there is the overheated area S1.

Further, the surface of the cold storage material container47may have recesses and projections, and the projections may be joined to the refrigerant tubes45.

Modifications of Seventh Embodiment

Modifications of the seventh embodiment will be described with reference toFIGS. 39 to 42. In the seventh embodiment, there has been described, as an example, one flow change type refrigerant passage, that is, the refrigerant passage structure1045in which the position in the inflow direction of the refrigerant is changed at one location in the second header tank52. However, another structure that includes at least one flow change type refrigerant passage may be employed. For example, an evaporator1040A illustrated inFIGS. 39 and 40uses one flow change type refrigerant passage in combination with a conventional two-turn type refrigerant passage. An evaporator1040B illustrated inFIGS. 41 and 42uses two flow change type refrigerant passages which are disposed in the inflow direction in combination. Further, a plurality of flow change type refrigerant passages may be disposed in the inflow direction. The refrigerant passages of the evaporator1040A and the evaporator1040B also make it possible to achieve a structure similar to the refrigerant passage structure1045of the seventh embodiment. Thus, it is possible to achieve an effect similar to the effect of the evaporator1040of the seventh embodiment.

Eighth Embodiment

An eight embodiment will be described with reference toFIGS. 43 to 45. An evaporator1140of the eighth embodiment differs from the evaporator1040of the seventh embodiment in that a function of an inner fin1147bis further provided in addition to the structure of the seventh embodiment as the heat transfer suppressor which suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area51which is formed due to flow rate variations in the refrigerant passage when the flow rate of the refrigerant is low. Specifically, as illustrated inFIGS. 43 to 45, the evaporator1140of the eighth embodiment differs from the evaporator1040of the seventh embodiment in that, in a cold storage material container1147which is in contact with the overheated area51(the back and downstream side, the front and upstream side), the inner fin1147bis not in contact with the overheated area51.

In other words, the inner fin1147bextends in the longitudinal direction (height direction) of the cold storage material container1147inside the cold storage material container1147. The inner fin1147bis not joined to the inner wall of the cold storage material container1147in a part where the cold storage material container1147is joined to refrigerant tubes45of the second group G2and the fourth group G4having the overheated area51(a cross section taken along line B7-B7inFIG. 43). Further, the inner fin1147bis joined to the inner wall of the cold storage material container1147in a part where the cold storage material container1147is in contact with refrigerant tubes45of the first group G1and the third group G3having no overheated area51(a cross section taken along line A7-A7inFIG. 43). The inner fin1147bfunctions as the heat transfer suppressor.

With the above structure, the evaporator1140of the eighth embodiment achieves an effect similar to the effect of the seventh embodiment. Further, since the inner fin1147bis not in contact with the cold storage material container1147in the overheated area S1, heat in the overheated area S1is less likely to be transferred to the cold storage material50inside the cold storage material container1147. Thus, it is possible to more appropriately cool the cold storage material inside the cold storage material container1147with cold in a non-overheated area without the influence of the heat in the overheated area S1.

A joining structure between the inner fin1147band the cold storage material container1147of the eighth embodiment is not limited to the above structure and may have another structure that makes a heat transfer amount from the refrigerant tube45to the cold storage material50through the inner fin1147bin the overheated area S1relatively smaller than a heat transfer amount in an area other than the overheated area S1. In other words, it may only be required to make the heat transfer performance of the inner fin1147bin the overheated area S1relatively lower than the other part. For example, similarly to the structure described in the first embodiment with reference toFIG. 11, the inner fin1171bmay be joined to the inner wall surface of an outer shell1147aof the cold storage material container1147with a relatively low joining ratio in a part that is in contact with the overheated area S1of the refrigerant tube45and joined to the inner wall surface with a relatively high joining ratio in a part that is in contact with an area other than the overheated area S1of the refrigerant tube45. It is possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1by making the heat transfer amount through the inner fin1147bin the overheated area S1relatively small or making the joining ratio between the inner fin1147band the cold storage material container1147in the overheated area S1relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator1140of the present embodiment.

Further, similarly to the structure described in the first embodiment with reference toFIG. 12, the corrugated shape of the inner fin1147bmay be continuous in the short direction (airflow direction) of the cold storage material container1147, that is, peaks and valleys of the inner fin1147bmay extend in the height direction. In this case, peaks and valleys of the inner fin1147bthat are in contact with the overheated area S1of the refrigerant tube45in the airflow direction are not joined to the inner wall surface of the outer shell1147aof the cold storage material container1147, and peaks and valleys of the inner fin1147bthat are in contact with an area other than the overheated area S1are joined to the inner wall surface. Also with the above structure, it is possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1and achieve an effect similar to the effect of the evaporator1140of the present embodiment.

Ninth Embodiment

A ninth embodiment will be described with reference toFIGS. 46 to 48. An evaporator1240of the ninth embodiment differs from the evaporator1040of the seventh embodiment in that a function of a cold storage material container1247is also provided in addition to the structure of the seventh embodiment as the heat transfer suppressor which suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1which is formed due to flow rate variations in the refrigerant passage when the flow rate of the refrigerant is low. Specifically, as illustrated inFIGS. 46 to 48, the evaporator1240of the ninth embodiment differs from the evaporator1040of the seventh embodiment in that the cold storage material container1247which is in contact with the overheated area S1(the back and downstream side, the front and upstream side) is not joined to the refrigerant tube45having the overheated area S1. Further, the evaporator1240of the ninth embodiment differs from the evaporator1040of the seventh embodiment in that no inner fin is disposed inside the cold storage material container1247.

In other words, the cold storage material container1247is separated from the refrigerant tubes45without being joined to the refrigerant tubes45in a part that is in contact with refrigerant tubes45of the second group G2and the fourth group G4having the overheated area S1(a cross section taken along line B8-B8inFIG. 46, an area1247c). Further, the cold storage material container1247is joined to the refrigerant tubes45in a part that is in contact with refrigerant tubes45of the first group G1and the third group G3having no overheated area S1(a cross section taken along line A8-A8inFIG. 46, an outer shell1247a). The cold storage material container1247functions as the heat transfer suppressor.

With the above structure, the evaporator1240of the ninth embodiment achieves an effect similar to the effect of the seventh embodiment. Further, since the cold storage material container1247is not in contact with the refrigerant tubes45in the overheated area S1, heat in the overheated area S1is less likely to be transferred to the cold storage material50inside the cold storage material container1247. Thus, it is possible to more appropriately cool the cold storage material50inside the cold storage material container1247with cold in a non-overheated area without the influence of the heat in the overheated area S1.

The shape of the cold storage material container1247of the ninth embodiment is not limited to the above shape and may have another structure that makes a heat transfer amount from the refrigerant tube45to the cold storage material50through the cold storage material container1247in the overheated area S1relatively smaller than a heat transfer amount in an area other than the overheated area S1. In other words, it may only be required to make the heat transfer performance of the cold storage material container1247in the overheated area S relatively lower than that in the other area. For example, similarly to the structure described in the second embodiment with reference toFIG. 23, the cold storage material container1247may be jointed to the refrigerant tube45with a relatively low joining ratio in a part (area1247c) that is in contact with the overheated area S1of the refrigerant tube45and joined to the refrigerant tube45with a relatively high joining ratio in a part (outer shell1247a) that is in contact with an area other than the overheated area S1of the refrigerant tube45. It is possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1by making the heat transfer amount of the cold storage material container1247in the overheated area S1relatively small or making the joining ratio between the cold storage material container1247and the refrigerant tube45relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator1240of the present embodiment

Tenth Embodiment

A tenth embodiment will be described with reference toFIGS. 49 to 51. An evaporator1340of the tenth embodiment differs from the evaporator1040of the seventh embodiment in that a function of a cold storage material container1247is also provided in addition to the structure of the seventh embodiment as the heat transfer suppressor which suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1which is formed due to flow rate variations in the refrigerant passage when the flow rate of the refrigerant is low. Specifically, as illustrated inFIGS. 49 to 51, the evaporator1340of the tenth embodiment differs from the evaporator1040of the seventh embodiment in that the cold storage material container1247which is in contact with the overheated area S1(the back and downstream side, the front and upstream side) is not joined to the refrigerant tube45having the overheated area S1.

In other words, an inner fin1347bextends in the longitudinal direction (height direction) of the cold storage material container1347inside the cold storage material container1347, and is joined to the inner wall of the cold storage material container1347over the entire area in the longitudinal direction. The cold storage material container1347is separated from the refrigerant tubes45without being joined to the refrigerant tubes45in a part that is in contact with refrigerant tubes45of the second group G2and the fourth group G4having the overheated area S1(a cross section taken along line B9-B9inFIG. 49, an area1347c). Further, the cold storage material container1347is joined to the refrigerant tubes45in a part that is in contact with refrigerant tubes45of the first group G1and the third group G3having no overheated area S1(a cross section taken along line A9-A9inFIG. 49, an outer shell1347a). The cold storage material container1347functions as the heat transfer suppressor.

With the above structure, the evaporator1340of the tenth embodiment achieves an effect similar to the effect of the seventh embodiment. Further, since the cold storage material container1347is not in contact with the refrigerant tubes45in the overheated area S1, heat in the overheated area S1is less likely to be transferred to the cold storage material50inside the cold storage material container1347. Further, since the inner fin1347bis disposed inside the cold storage material container1347, cold in a non-overheated side is easily transferred to the overheated area side. Thus, it is possible to more appropriately cool the cold storage material50inside the cold storage material container1347with cold in the non-overheated area without the influence of the heat in the overheated area S1.

Similarly to the eighth embodiment, the evaporator1340of the tenth embodiment may have a structure in which the inner fin1347bis not joined to the inner wall of the cold storage material container1347in a part (area1347c) where the cold storage material container1347is joined to the refrigerant tubes45of the second group G2and the fourth group G4having the overheated area S1. With the above structure, the inner fin1347bis not joined to the cold storage material container1347, that is, the refrigerant tubes45in the overheated area S1. Thus, heat from the overheated refrigerant is further less likely to be transferred to the inside of the cold storage material50.

The shape of the cold storage material container1347of the tenth embodiment is not limited to the above shape and may have another structure that makes a heat transfer amount from the refrigerant tube45to the cold storage material50through the cold storage material container1247in the overheated area S1relatively smaller than a heat transfer amount in an area other than the overheated area S1. In other words, it may only be required to make the heat transfer performance of the cold storage material container1347in the overheated area S relatively lower than that in the other part. For example, similarly to the structure described in the second embodiment with reference toFIG. 23, the cold storage material container1347may be jointed to the refrigerant tube45with a relatively low joining ratio in a part (area1347c) that is in contact with the overheated area S1of the refrigerant tube45and joined to the refrigerant tube45with a relatively high joining ratio in a part (outer shell1347a) that is in contact with an area other than the overheated area S1of the refrigerant tube45. It is possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1by making the heat transfer amount of the cold storage material container1347in the overheated area S1relatively small or making the joining ratio between the cold storage material container1347and the refrigerant tube45relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator1340of the present embodiment.

Further, when there is applied a structure that suppresses heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1by a joining structure between the inner fin1347band the cold storage material container1347similarly to the eighth embodiment, a structure similar to the structure described in the first embodiment with reference toFIG. 11can be applied. Specifically, the inner fin1347bis joined to the inner wall surface of the outer shell1347aof the cold storage material container1347with a relatively low joining ratio in a part that is in contact with the overheated area S1of the refrigerant tube45and joined to the inner wall surface with a relatively high joining ratio in a part that is in contact with an area other than the overheated area S1of the refrigerant tube45. It is possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1also by making the joining ratio between the inner fin1347band the cold storage material container1347relatively low in this manner. As a result, it is possible to obtain an effect similar to the effect of the evaporator1340of the present embodiment

Further, similarly to the structure described in the first embodiment with reference toFIG. 12, the corrugated shape of the inner fin1347bmay be continuous in the short direction (airflow direction) of the cold storage material container1347, that is, peaks and valleys of the inner fin1347bmay extend in the height direction. Also with the above structure, it is possible to suppress heat transfer from the refrigerant tube45to the cold storage material50in the overheated area S1and obtain an effect similar to the effect of the evaporator1340of the present embodiment.

Eleventh Embodiment

An eleventh embodiment will be described with reference toFIG. 52. An evaporator1440of the eleventh embodiment differs from the evaporator1040of the seventh embodiment (refer toFIGS. 33 to 35) in that, in a plurality of refrigerant tubes45, a high-melting point cold storage material50A is disposed in a part that is in contact with the second group G2and the fourth group G4having an overheated area S1, the high-melting point cold storage material50A having a relatively high melting point compared to the other part (the first group G1in the present embodiment), and the high-melting point cold storage material50A is disposed also in a part that is in contact with the third group G3having an overheated area S2.

As described above with reference toFIG. 34, in the flow change type refrigerant flow passage structure1045, the overheated area S1is formed in the second group G2and the fourth group G4of the refrigerant tubes45due to flow rate variations in the refrigerant passage when the flow rate of the refrigerant is low. Further, the overheated area S2is formed near the outlet of the third group G3of the refrigerant tubes45by a mechanism similar to that of the overheated area S of the first to sixth embodiments. In the eleventh embodiment, the high-melting point cold storage material50A is stored inside each of cold storage material containers47which are in contact with the refrigerant tubes45having the overheated areas S1, S2(that is, the second group G2, the third group G3, and the fourth group G4).

As illustrated inFIG. 52, in the cold storage material container47that is in contact with both of the first group G1and the fourth group G4of the refrigerant tubes45, a part that is in contact with the first group G1(the half part on the downstream side in the airflow direction) is filled with the cold storage material50having a normal melting point, and a part that is in contact with the fourth group G4(the half part on the upstream side in the airflow direction) is filled with the high-melting point cold storage material50A. Such a structure can be achieved, for example, by partitioning an internal space of a single cold storage material container47with a partition plate which is embedded inside the cold storage material container47at a substantially intermediate position in the airflow direction. In the cold storage material container47that is in contact with both of the second group G2and the third group G3of the refrigerant tubes45, the entire internal space thereof is merely filled with the high-melting point cold storage material50A.

When the melting point of the cold storage material is increased by using the high-melting point cold storage material50A, a temperature difference from a refrigerant which cools the cold storage material increases. Thus, the cold storage material is more easily cooled (more easily congealed). For example, it is assumed that a temperature of the refrigerant in a normal area of the refrigerant tube45is −3° C., a temperature of the refrigerant in the overheated areas S1, S2of the refrigerant tube45is 0° C., and a melting point of the cold storage material which performs heat exchange with the refrigerant in the normal area of the refrigerant tube45is 5° C. In this case, when a melting point of the cold storage material which performs heat exchange with the refrigerant in the overheated areas S1, S2of the refrigerant tube45is substantially equal to the melting point of the cold storage material in the normal area, congelation of the cold storage material in the overheated areas S1, S2becomes relatively difficult, and the congealability of the cold storage material in the overheated areas S1, S2becomes lower than that in the normal area. On the other hand, when the melting point of the cold storage material in the overheated areas S1, S2is made higher than the melting point of the cold storage material in the normal area by a temperature difference (here, +3° C.) between the refrigerant in the normal area and the refrigerant in the overheated areas S1, S2, the congealability of the cold storage material in the overheated areas S1, S2becomes equal to that in the normal area. Further, when the melting point of the cold storage material in the overheated areas S1, S2is made higher than the melting point of the cold storage material in the normal area by more than the temperature difference between the refrigerant in the normal area and the refrigerant in the overheated areas S1, S2, the congealability of the cold storage material in the overheated areas S1, S2becomes higher than that in the normal area.

As described above, the evaporator1440of the eleventh embodiment has the structure in which the high-melting point cold storage material50A is disposed in each part that is in contact with the refrigerant tubes45having the overheated areas S1, S2. Thus, it is possible to equalize the congealability of the cold storage materials without depending on whether the refrigerant which performs heat exchange with the cold storage material is located in the overheated areas S1, S2or in the normal area. Accordingly, it is possible to reduce the influence of the overheated areas S1, S2and improve the heat storage and release performance of the evaporator1440.

Modification of Eleventh Embodiment

In the eleventh embodiment, there has been described, as an example, the structure in which the high-melting point cold storage material50A is filled inside the cold storage material container47that is in contact with the refrigerant tubes45of the third group G3having the overheated area S2over the entire area of the cold storage material container47in the height direction. However, it may only be required that the high-melting point cold storage material50A be filled at least in a part that is in contact with the overheated area S2. For example, the high-melting point cold storage material50A may be stored only in a part that is in contact with the vicinity of the outlet side passage having the overheated area S2in the cold storage material container47that is in contact with the refrigerant tubes45of the third group G3. Such a structure can be achieved, for example, by partitioning an internal space of a single cold storage material container47with a partition plate which is embedded inside the cold storage material container47along a part overlapping the overheated area S2(e.g., a quarter part of the cold storage material container47on the upstream side in the airflow direction and the upper side in the height direction).

Twelfth Embodiment

A twelfth embodiment will be described with reference toFIG. 53. An evaporator1540of the twelfth embodiment differs from the evaporator1040of the seventh embodiment (refer toFIGS. 33 to 35) in that, in a plurality of refrigerant tubes45, a high-melting point cold storage material50A is disposed in a part that is in contact with the second group G2and the fourth group G4having an overheated area51. In other words, the evaporator1540of the twelfth embodiment differs from the evaporator1440of the eleventh embodiment (refer toFIG. 52) in that the high-melting point cold storage material50A is not disposed in a part that is in contact with the third group G3having an overheated area S2.

As illustrated inFIG. 53, in the cold storage material container47that is in contact with both of the second group G2and the third group G3of the refrigerant tubes45, a part that is in contact with the third group G3(the half part on the upstream side in the airflow direction) is filled with the cold storage material50having a normal melting point, and a part that is in contact with the second group G2(the half part on the downstream side in the airflow direction) is filled with the high-melting point cold storage material50A. The structure of the cold storage material container47that is in contact with both of the first group G1and the fourth group G4of the refrigerant tubes45is similar to that in the eleventh embodiment described above with reference toFIG. 52.

The evaporator1540of the twelfth embodiment has the structure in which the high-melting point cold storage material50A is disposed in the part that is in contact with the refrigerant tube45having the overheated area S1similarly to the evaporator1440of the eleventh embodiment. Thus, it is possible to equalize the congealability of the cold storage materials without depending on whether the refrigerant which performs heat exchange with the cold storage material is located in the overheated area S1or in the normal area similarly to the eleventh embodiment. Accordingly, it is possible to achieve an effect of reducing the influence of the overheated area S1and improving the heat storage and release performance.

Further, in the evaporator1540of the twelfth embodiment, the cold storage materials having two different melting points (the cold storage material50and the high-melting point cold storage material50A) are stored inside the cold storage material container47equally in the right and left (with the same amount in the airflow direction) corresponding to a distribution of the refrigerant temperature (the distribution in the order from the normal area to the overheated area S1in the airflow direction). With the above structure, the cold storage materials having two different melting points are equally congealed. As a result, it is possible to equalize a blowout temperature distribution during heat release.

Thirteenth Embodiment

A thirteenth embodiment will be described with reference toFIG. 54. An evaporator1640of the thirteenth embodiment differs from the evaporator40of the first embodiment in that the cold storage material in a part that is in contact with the overheated area S is a high-melting point cold storage material50A.

As described above with reference toFIG. 5, in the so-called four-turn type refrigerant passage structure, the overheated area S is formed by evaporation of a refrigerant in the substantially half area on the upper side in the height direction in the refrigerant tubes45of the fourth group G4, that is, near the outlet of the refrigerant passage. In the thirteenth embodiment, the high-melting point cold storage material50A is stored in each cold storage material container47that is in contact with the refrigerant tube45having the overheated area S (that is, the fourth group G4).

In the thirteenth embodiment, it may only be required that at least the cold storage material in a part that is in contact with the overheated area S be the high-melting point cold storage material50A. For example, the high-melting point cold storage material50A may be filled inside the cold storage material container47that is in contact with the refrigerant tube45of the fourth group G4having the overheated area S over the entire area in the height direction of the cold storage material container47or may be filled only in a part that is in contact with the overheated area S.

The evaporator1640of the thirteenth embodiment has the structure in which the high-melting point cold storage material50A is disposed in the part that is in contact with the refrigerant tube45having the overheated area S1similarly to the evaporator1440of the eleventh embodiment. Thus, also in the four-turn type refrigerant passage structure, it is possible to equalize the congealability of the cold storage materials without depending on whether the refrigerant which performs heat exchange with the cold storage material is located in the overheated area S1or in the normal area similarly to the flow change type refrigerant flow passage structure1045of the eleventh embodiment. Accordingly, it is possible to achieve an effect of reducing the influence of the overheated area S and improving the heat storage and release performance. The structure of the third embodiment can also be applied to the second to sixth embodiments relating to the four-turn type refrigerant passage structure.

Fourteenth Embodiment

A fourteenth embodiment will be described with reference toFIG. 55. An evaporator1740of the fourteenth embodiment differs from each of the above embodiments in that a pair of partition plates47dwhich partitions an internal space of the cold storage material container47in the longitudinal direction (that is, the height direction) which is the extending direction of the refrigerant tubes45is disposed inside the cold storage material container47.

As illustrated inFIG. 55, one of the partition plates47d(the right plate inFIG. 55) has a space in an end on one side in the longitudinal direction (the lower side in the height direction inFIG. 55) of the cold storage material container47. Further, the other one of the partition plates47d(the left plate inFIG. 55) has a space in an end on the other side in the longitudinal direction (on the upper side in the height direction inFIG. 55) of the cold storage material container47. The partition plates47dare disposed at substantially regular intervals in the airflow direction. Further, the cold storage material container47is provided with a cold storage material filling pipe47eon one of side walls in the airflow direction that is closer to the right partition plate.

The cold storage material50is filled into the cold storage material container47through the cold storage material filling pipe47e. At this time, an approximately 15% of space is typically left on the upper side of the inside of the cold storage material container47without completely filling the internal space of the cold storage material container47with the cold storage material50as a countermeasure against expansion by freezing. For example, as illustrated inFIG. 55, a space having an approximately height C1is left on the upper end in the internal space. The overheated areas S1, S2described in the above embodiments are mainly formed on the upper side in the height direction of the refrigerant tubes45. Thus, in a conventional structure, the upper side in the height direction of the cold storage material container47may be less cooled, and a cooling failure may occur.

In the structure of the fourteenth embodiment, the internal space of the cold storage material container47is partitioned into three areas by the pair of partition plates47d, and the partitioned areas lie in a line in series. Thus, when the cold storage material50is injected with an approximately 15% of space left as a countermeasure against expansion by freezing in a manner similar to a conventional manner, as illustrated inFIG. 55, a space47fis formed only in an area communicating with the cold storage material filling pipe47e, and each of the other two areas on the back side is filled with the cold storage material50over the entire area in the height direction thereof. That is, although a height c2from the upper end is larger than a conventional height c1when only the space47fis viewed, there is no position where the cold storage material50is not present in the height direction when the entire internal space of the cold storage material container47is viewed. In other words, when the internal space of the cold storage material container47is viewed in the airflow direction, the cold storage material50is disposed over the entire area in the height direction. Accordingly, it is possible to prevent formation of a space on the upper end inside the cold storage material container47and eliminate an uncooled part on the upper side in the height direction of the cold storage material container47.

It may only be required that at least a pair of partition plates47dbe disposed inside the cold storage material container47, and a plurality of pairs of partition plates may be provided.

Fifteenth Embodiment

A fifteenth embodiment will be described with reference toFIG. 56. An evaporator1840of the fifteenth embodiment differs from the evaporator40of the first embodiment in that the cold storage material container47which is joined to the refrigerant tube45having the overheated area S is not disposed in a part that is in contact with the overheated area S of the refrigerant tube45and disposed only in a part that is in contact with an area other than the overheated area S of the refrigerant tube45.

As described above with reference toFIG. 5, in the so-called four-turn type refrigerant passage structure, the overheated area S is formed by evaporation of a refrigerant in the substantially half area on the upper side in the height direction in the refrigerant tubes45of the fourth group G4, that is, near the outlet of the refrigerant passage. In the fifteenth embodiment, as illustrated inFIG. 56, the cold storage material container47that is in contact with the refrigerant tube45having the overheated area S, that is, the refrigerant tube45of the fourth group G4is not disposed in an area having the overheated area S (the vicinity of the outlet of the refrigerant passage).

With the above structure, the evaporator1840of the fifth embodiment is capable of cutting heat exchange between the refrigerant and the cold storage material50in the overheated area S and improve the cooling efficiency. Accordingly, it is possible to further improve fuel consumption by increasing an off time of an air conditioner during an idle stop of a vehicle equipped with the evaporator1840by facilitating congelation of the cold storage material50to increase cooling time as compared to a conventional product. The structure of the fifteenth embodiment can also be applied to the second to sixth embodiments relating to the four-turn type refrigerant passage structure.

The embodiments of the present disclosure have been described above with reference to concrete examples. However, the present disclosure is not limited to the concrete examples described above. That is, the concrete examples with design modifications appropriately added by those skilled in the art are also included in the scope of the present disclosure as long as they have features of the present disclosure. For example, each element included in each of the concrete examples, and the arrangement, material, condition, shape, and size thereof are not limited to the illustrated one and can be appropriately modified. Further, elements included in the respective embodiments described above can be combined as long as the combination is technically feasible. These combinations are also included in the scope of the present disclosure as long as they have the features of the present disclosure.

For example, the method described in the first to sixth embodiments for reducing the influence on cold storage by the overheated areas S, S2which are formed by evaporation of the refrigerant near the outlet of the refrigerant passage can be combined with the structures of the seventh to tenth embodiments.

In the above embodiments, there has been described, as an example, the structure in which, in the evaporator40, the cold storage material container47is disposed between two refrigerant tubes45and joined to the two refrigerant tubes45, and the air passage53is formed on the opposite side of the cold storage material container47in each of the refrigerant tubes45. However, the present disclosure is not limited to the above structure. For example, the refrigerant tubes45and the cold storage material containers47may be formed as integrated members extending in the same direction, and the air passages53may be formed in spaces between these members.

In the above embodiments, there has been described, as an example, the structure in which the cold storage material50is stored in the cold storage material container47. However, the present disclosure is not limited to the above structure. For example, the cold storage material50may not be stored in the cold storage material container47, but may have direct contact with the refrigerant tube45so as to directly transfer heat from the refrigerant tube45to the cold storage material50.