US20100223949A1

US20100223949A1 - Evaporator with cool storage function

Info

Publication number: US20100223949A1
Application number: US12/656,971
Authority: US
Inventors: Naohisa Higashiyama; Hironaka Sasaki
Original assignee: Showa Denko KK
Current assignee: Mahle Behr Thermal Systems Japan Ltd
Priority date: 2009-03-06
Filing date: 2010-02-22
Publication date: 2010-09-09
Also published as: CN101825377A; CN101825377B

Abstract

An evaporator with a cool storage function includes flat refrigerant flow tubes and flat cool storage material containers each brazed to one side surface of the corresponding refrigerant flow tube. A plurality of sets each composed of refrigerant flow tubes and a cool storage material container are disposed such that they are spaced from one another. A fin is disposed in an air-passing clearance between adjacent sets, and is joined to the corresponding refrigerant flow tubes and the corresponding cool storage material container. Front portions of the cool storage material containers and the fins project frontward from the refrigerant flow tubes, and an internal-volume-increasing portion, whose container height is greater than that of the container body portion, is provided at the frontward projecting portion of each cool storage material container. Fins are brazed to opposite side surfaces of the internal-volume-increasing portion of each cool storage material container.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an evaporator with a cool storage function for use in a car air conditioner for a vehicle in which an engine serving as a drive source for a compressor is temporarily stopped when the vehicle is stopped.
In recent years, in order to protect the environment and improve fuel consumption of automobiles, there has been proposed an automobile designed to automatically stop the engine when the automobile stops, for example, so as to wait for a traffic light to change.
Incidentally, an ordinary car air conditioner has a problem in that, when an engine of an automobile in which the air conditioner is mounted is stopped, a compressor driven by the engine is stopped, and supply of refrigerant to an evaporator stops, whereby the cooling capacity of the air conditioner sharply drops.
As one measure to solve such a problem, imparting a cool storage function to the evaporator has been considered, to thereby enable cooling of a vehicle compartment by making use of cool stored in the evaporator, when the compressor stops as a result of stoppage of the engine.
An evaporator having a cool storage function has been proposed (see, for example, Japanese Patent No. 4043776). The proposed evaporator includes a pair of refrigerant header sections disposed apart from each other, and a plurality of flat refrigerant flow tubes disposed between the two refrigerant header sections such that their width direction coincides with an air flow direction, and they are spaced from one another in the longitudinal direction of the refrigerant header sections. Opposite ends of the refrigerant flow tubes are connected to the two refrigerant header sections, respectively. The evaporator further includes a plurality of hollow cool storage material containers disposed such that their width direction coincides with the air flow direction. Each of the cool storage material containers is fixedly provided on one side of a corresponding refrigerant flow tube and contains a cool storage material therein. The dimension of each cool storage material container with respect to the thickness direction is made uniform over the entirety of the cool storage material container. A plurality of sets each composed of refrigerant flow tubes and a cool storage material container are disposed apart from each other, and a space between adjacent pairs each composed of refrigerant flow tubes and a cool storage material container serves as an air-passing clearance. A fin is disposed in the air-passing clearance, and is joined to the refrigerant flow tube and the cool storage material container.
In the case of the evaporator having a cool storage function disclosed in the publication, when refrigerant of low temperature flows through the refrigerant flow tubes, cool is stored in the cool storage material within the cool storage material container.
However, in the case of the evaporator having a cool storage function disclosed in the publication, when an increase in the amount of the cool storage material in the cool storage material container is desired in order to improve the cool storage performance, the lengths of the cool storage material containers and the refrigerant flow tubes must be increased, and the container height (dimension with respect to the thickness direction) of the cool storage material containers must be increased over the entirety thereof. However, when the lengths of the cool storage material containers and the refrigerant flow tubes are increased, the size of the heat exchange core section of the evaporator increases, with a resultant increase in weight and deterioration in space saving performance. Further, when the container height of the cool storage material containers is increased over the entirety thereof without changing the dimension of the heat exchange core section, the air passage area of each air-passing clearance decreases, and air passage resistance increases.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above problems and to provide an evaporator with a cool storage function of reduced size and weight which can suppress an increase in air passage resistance.
To fulfill the above object, the present invention comprises the following modes.
1) An evaporator with a cool storage function comprising a plurality of flat refrigerant flow tube sections disposed such that their width direction coincides with an air flow direction and they are spaced from one another, and a plurality of flat cool storage material containers disposed such that their width direction coincides with the air flow direction, each of the cool storage material containers being in contact with one side surface of the corresponding refrigerant flow tube section and containing a cool storage material, wherein
an internal-volume-increasing portion is provided at an upstream or downstream portion of each cool storage material container with respect to the air flow direction, and has a container height greater than that of the remaining portion of the cool storage material container, the container height being a dimension in a thickness direction of the cool storage material container.
2) An evaporator with a cool storage function according to par. 1), wherein a plurality of sets each composed of a refrigerant flow tube section and a cool storage material container are disposed such that they are spaced from one another in a direction perpendicular to the width direction of the refrigerant flow tube sections; a space between adjacent sets each composed of a refrigerant flow tube section and a cool storage material container serves as an air-passing clearance; and a fin is disposed in the air-passing clearance, and is joined to the corresponding refrigerant flow tube section and the corresponding cool storage material container.
3) An evaporator with a cool storage function according to par. 2), wherein respective upstream or downstream portions of each cool storage material container and each fin project outward, with respect to the air flow direction, from the refrigerant flow tube sections; the internal-volume-increasing portion is provided at a portion of each cool storage material container, which portion projects outward, with respect to the air flow direction, from the refrigerant flow tube sections; and the fins are joined to opposite side surfaces of the internal-volume-increasing portion of each cool storage material container.
4) An evaporator with a cool storage function according to par. 3), wherein the interiors of the cool storage material containers communicate with one another at the internal-volume-increasing portions thereof.
5) An evaporator with a cool storage function according to par. 3), wherein respective downstream portions of each cool storage material container and each fin project downstream from the refrigerant flow tube sections; and the internal-volume-increasing portion is provided at a portion of each cool storage material container, which portion projects doWnstream from the refrigerant flow tube sections.
6) An evaporator with a cool storage function according to par. 2), wherein when the container height of each cool storage material container, excluding the internal-volume-increasing portion, is taken as 1, a tube section height, which is a dimension of each refrigerant flow tube section in a thickness direction thereof, is 0.25 to 2.0, and a fin height, which is a dimension of each fin in a direction of arrangement of the sets each composed of a refrigerant flow tube section and a cool storage material container, is 1.0 to 5.5.
7) An evaporator with a cool storage function according to par. 6), wherein the container height of each cool storage material container, excluding the internal-volume-increasing portion, is 1.5 to 4.0 mm, the tube section height of each refrigerant flow tube section is 1.0 to 3.0 mm, and the fin height is 4.0 to 8.0 mm.
8) An evaporator with a cool storage function according to par. 1), wherein a plurality of refrigerant flow tube sections are juxtaposed in the air flow direction; a tube section height of at least the refrigerant flow tube section disposed on the downstream end, the tube section height being a dimension in the thickness direction thereof, is smaller than that of the remaining refrigerant flow tube section(s); and the internal-volume-increasing portion is provided at a portion of each cool storage material container, which portion is in contact with the refrigerant flow tube section having the smaller tube section height.
According to the evaporator with a cool storage function of par. 1) or 2), the internal-volume-increasing portion whose container height (dimension in the thickness direction of the cool storage material container) is greater than that of the remaining portion is provided on the upstream portion or downstream portion of the cool storage material container. Therefore, as compared with the case where the container height of the cool storage material container is uniform over the entirety thereof, the amount of the cool storage material charged into the cool storage material container can be increased without increasing the lengths of the cool storage material container and the refrigerant flow tube sections or increasing the container height of the cool storage material container over the entirety thereof. Accordingly, the size and weight of the evaporator can be reduced as compared with the case of a conventional evaporator with a cool storage function. In addition, in the case where, as in the evaporator with a cool storage function of par. 3), respective upstream or downstream portions of each cool storage material container and each fin project outward, with respect to the air flow direction, from the refrigerant flow tube sections, and the internal-volume-increasing portion is provided at a portion of each cool storage material container which portion projects outward, with respect to the air flow direction, from the refrigerant flow tube sections, a decrease in the area of the air-passing clearances stemming from provision of the internal-volume-increasing portions can be suppressed. Therefore, even when the dimension of the heat exchange core section is not changed, an increase in air passage resistance can be suppressed. Further, in the case where, as in the evaporator with a cool storage function of par. 6), the internal-volume-increasing portion is provided at a portion of the cool storage material container which portion is in contact with the refrigerant flow tube section having a smaller tube section height, a decrease in the area of the air-passing clearances stemming from provision of the internal-volume-increasing portions can be suppressed. Therefore, even when the dimension of the heat exchange core section is not changed, an increase in air passage resistance can be suppressed.
According to the evaporator with a cool storage function of par. 3), respective upstream or downstream portions of each cool storage material container and each fin project outward, with respect to the air flow direction, from the refrigerant flow tube sections; the internal-volume-increasing portion is provided at a portion of each cool storage material container which portion projects outward, with respect to the air flow direction, from the refrigerant flow tube sections; and the fins are joined to opposite side surfaces of the internal-volume-increasing portion of each cool storage material container. Therefore, as compared with the case where the container height of the cool storage material container is uniform over the entirety thereof, the amount of the cool storage material charged into the cool storage material container can be increased without increasing the lengths of the cool storage material container and the refrigerant flow tube sections or increasing the container height of the cool storage material container over the entirety thereof. Accordingly, the size and weight of the evaporator can be reduced as compared with the case of a conventional evaporator with a cool storage function. In addition, a decrease in the area of the air-passing clearances stemming from provision of the internal-volume-increasing portions can be suppressed. Therefore, even when the dimension of the heat exchange core section is not changed, an increase in air passage resistance can be suppressed.
Further, when a compressor stops as a result of stoppage of an engine, cool stored in the cool storage material within the internal-volume-increasing portion of each cool storage material container is transmitted to air passing through the corresponding air-passing clearances from the opposite side surfaces of the internal-volume-increasing portion via the fins fixed to the opposite side surfaces of the internal-volume-increasing portion. Thus, cool releasing performance is improved.
According to the evaporator with a cool storage function of par. 4), the interiors of the cool storage material containers communicate with one another at the internal-volume-increasing portions thereof. Therefore, through formation of a cool-storage-material charging opening in the internal-volume-increasing portion of one cool storage material container and an air bleeding opening in the internal-volume-increasing portion of another cool storage material container, an operation of charging the cool storage material into the mutually connected cool storage material containers becomes easier.
According to the evaporator with a cool storage function of par. 5), the internal-volume-increasing portion containing a larger amount of the cool storage material is present in a region where the air flowing through the corresponding air-passing clearance has a decreased temperature. Therefore, the cool storage material can be cooled efficiently, whereby cool storage performance is improved.
According to the evaporator with a cool storage function of par. 8), a plurality of refrigerant flow tube sections are juxtaposed in the air flow direction; a tube section height of at least the refrigerant flow tube section disposed on the downstream end, the tube section height being a dimension in the thickness direction thereof, is smaller than that of the remaining refrigerant flow tube section(s); and the internal-volume-increasing portion is provided at a portion of each cool storage material container which portion is in contact with the refrigerant flow tube section having the smaller tube section height. Therefore, as compared with the case where the container height of the cool storage material container is uniform over the entirety thereof, the amount of the cool storage material charged into the cool storage material container can be increased without increasing the lengths of the cool storage material container and the refrigerant flow tube sections or increasing the container height of the cool storage material container over the entirety thereof. Accordingly, the size and weight of the evaporator can be reduced as compared with the case of a conventional evaporator with a cool storage function. In addition, a decrease in the area of the air-passing clearances stemming from provision of the internal-volume-increasing portions can be suppressed. Therefore, even when the dimension of the heat exchange core section is not changed, an increase in air passage resistance can be suppressed. Further, since the internal-volume-increasing portion containing a larger amount of the cool storage material is present in a region where the air flowing through the corresponding air-passing clearance has a decreased temperature, the cool storage material can be cooled efficiently, whereby cool storage performance is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cut-away perspective view showing the overall structure of an evaporator with a cool storage function according to the present invention;

FIG. 2 is a partially omitted enlarged sectional view taken along line A-A of FIG. 1;

FIG. 3 is an enlarged sectional view taken along line B-B of FIG. 2;

FIG. 4 is an enlarged sectional view taken along line C-C of FIG. 2;

FIG. 5 is a perspective view showing a plurality of cool storage material containers united together;

FIG. 6 is an exploded perspective view showing a single cool storage material container;

FIG. 7 is a graph showing a relation between cool releasing time and container height of the container body of each cool storage material container of the evaporator with a cool storage function shown in FIGS. 1 to 6;

FIG. 8 is a graph showing a relation between air passage resistance and container height of the container body of each cool storage material container of the evaporator with a cool storage function shown in FIGS. 1 to 6;

FIG. 9 is a graph showing a relation between cool storing time and container height of the container body of each cool storage material container of the evaporator with a cool storage function shown in FIGS. 1 to 6;

FIG. 10 is a graph showing a relation between air passage resistance and tube height of the refrigerant flow tubes of the evaporator with a cool storage function shown in FIGS. 1 to 6;

FIG. 11 is a graph showing a relation between air passage resistance and fin height of corrugated fins of the evaporator with a cool storage function shown in FIGS. 1 to 6; and

FIG. 12 is a sectional view corresponding to FIG. 3 and showing another embodiment of the evaporator with a cool storage function according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will next be described with reference to the drawings.
In the following description, the downstream side (a direction represented by arrow X in FIGS. 1 to 4) with respect to an air flow direction will be referred to as the “front,” and the opposite side as the “rear.” Further, the upper, lower, left-hand, and right-hand sides as viewed rearward from the front side; i.e., the upper, lower, left-hand, and right-hand sides of FIG. 1, will be referred to as “upper,” “lower,” “left, and “right,” respectively.
In the following description, the term “aluminum” encompasses aluminum alloys in addition to pure aluminum.
FIG. 1 shows the overall configuration of an evaporator with a cool storage function according to the present invention, and FIGS. 2 to 6 show the configurations of essential portions of the evaporator.
As shown in FIGS. 1 and 2, an evaporator with a cool storage function 1 includes a first header tank 2 and a second header tank 3 formed of aluminum and disposed apart from each other in the vertical direction such that they extend in the left-right direction; and a heat exchange core section 4 provided between the two header tanks 2 and 3.
The first header tank 2 includes a refrigerant inlet header section 5 located on the front side (downstream side with respect to the air flow direction); and a refrigerant outlet header section 6 located on the rear side (upstream side with respect to the air flow direction) and united with the refrigerant inlet header section 5. A refrigerant inlet 7 is provided at the right end of the refrigerant inlet header section 5, and a refrigerant outlet 8 is provided at right end of the refrigerant outlet header section 6. The second header tank 3 includes a first intermediate header section 9 located on the front side, and a second intermediate header section 11 located on the rear side and united with the first intermediate header section 9. The respective interiors of the first and second intermediate header sections 9 and 11 of the second header tank 3 are connected together via a communication member 12 which extends across and is joined to the right ends of the intermediate header sections 9 and 11 and which has a flow passage formed therein.
As shown in FIGS. 1 to 4, the heat exchange core section 4 includes a plurality of sets each composed of a plurality of (two in the present embodiment) vertically extending flat refrigerant flow tubes (refrigerant flow tube sections) 13 formed of aluminum extrudate, and a vertically extending flat cool storage material container 14 formed of aluminum. The refrigerant flow tubes 13 are disposed such that their width direction coincides with the front-rear direction and they are spaced from each other in the front-rear direction. The cool storage material container 14 is disposed such that its width direction coincides with the front-rear direction, and is brought into contact with selected side surfaces (left side surfaces in the present embodiment) of the front and rear refrigerant flow tubes 13. In this state, the cool storage material container 14 is brazed to the front and rear refrigerant flow tubes 13. The cool storage material container 14 contains a cool storage material (not shown) therein. The plurality of sets 15 each composed of front and rear refrigerant flow tubes 13 and one cool storage material container 14 are disposed such that the sets are spaced from one another in the left-right direction (direction perpendicular to the width direction of the refrigerant flow tubes 13).
Upper-end portions of the front refrigerant flow tubes 13 are connected to the refrigerant inlet header section 5, and lower end portions of the front refrigerant flow tubes 13 are connected to the first intermediate header section 9. Further, upper end portions of the rear refrigerant flow tubes 13 are connected to the refrigerant outlet header section 6, and lower end portions of the rear refrigerant flow tubes 13 are connected to the second intermediate header section 11. A space between adjacent sets 15 each composed of two refrigerant flow tubes 13 and one cool storage material container 14 serves an air-passing clearance 16. A corrugated fin 17 formed of aluminum is disposed in the air-passing clearance 16, and is brazed to the corresponding refrigerant flow tubes 13 and the corresponding cool storage material container 14. Further, the corrugated fin 17 formed of aluminum is disposed on the outer sides of two sets 15 located at the left and right ends, respectively. The right end corrugated fin 17 is brazed to the front and rear refrigerant flow tubes 13 located at the right end, and the left end corrugated fin 17 is brazed to the cool storage material container 14 located at the left end. A side plate 18 formed of aluminum is disposed on the outer side of each of the corrugated fins 17 located at the left and right ends, respectively, and is brazed to the corresponding corrugated fin 17.
As shown in FIGS. 2 to 5, each cool storage material container 14 includes a container body 21 and an internal-volume-increasing portion 22. The container body 21 is located rearward of the front edges of the refrigerant inlet header section 5 and the first intermediate header section 9, and is brazed to the front and rear refrigerant flow tubes 13 of the corresponding set 15. The internal-volume-increasing portion 22 extends from the front edge of the container body 21 such that the volume-increasing portion 22 projects frontward from the front edges of the refrigerant inlet header section 5 and the first intermediate header section 9. The dimension of the internal-volume-increasing portion 22 as measured in the thickness direction (left-right direction) is greater than that of the container body 21. The container height of the internal-volume-increasing portion 22 is equal to the sum of a tube height (tube section height), which is the dimension of the refrigerant flow tubes 13 as measured in the thickness direction and the container height of the container body 21 of each cool storage material container 14. The internal-volume-increasing portion 22 is swelled rightward only in relation to the container body 21, and the left side surface of the internal-volume-increasing portion 22 is flush with the left side surface of the container body 21. Upper and lower end portions of the internal-volume-increasing portion 22 of each cool storage material container 14 project upward and downward, respectively, from the upper and lower ends of the container body 21. Each of the projecting portions of the internal-volume-increasing portion 22 has left and right tank-forming portions 23 swelled outward with respect to the left-right direction. The tank-forming portions 23 of the internal-volume-increasing portions 22 of adjacent cool storage material containers 14 are brazed to each other, whereby all the cool storage material containers 14 are united. Further, a communication hole 24 formed in a swelled end wall portion of each of the tank-forming portions 23 establishes communication between the interiors of the tank-forming portions 23 of the internal-volume-increasing portions 22 of adjacent cool storage material containers 14. The upper tank-forming portions 23 of the internal-volume-increasing portions 22 of all the cool storage material containers 14 form an upper communication tank 25, and the lower tank-forming portions 23 of the internal-volume-increasing portions 22 of all the cool storage material containers 14 form a lower communication tank 25. Thus, the interiors of all the cool storage material containers 14 are connected together via the upper and lower communication tanks 25. Although not illustrated, a cool-storage-material charging opening is formed in one of the upper and lower communication tanks 25, and an air-bleeding opening is formed in the other of the upper and lower communication tanks 25. A cool storage material is charged into all the cool storage material containers 14 via the cool-storage-material charging opening. After the cool storage material is charged into the cool storage material containers 14, the cool-storage-material charging opening and the air-bleeding opening are closed by appropriately means. Examples of the cool storage material to be charged into the cool storage material containers 14 include a water-based cool storage material and a paraffin-based cool storage material having an adjusted freezing point of about 3 to 10° C. Further, preferably, the amount of the cool storage material charged into the cool storage material containers 14 is determined so that the cool storage material fills all the cool storage material containers 14 up to their upper ends.
As shown in FIG. 6, each cool storage material container 14 is composed of two generally rectangular, vertically elongated aluminum plates 26 and 27 brazed together along their peripheral edge portions. Both the aluminum plates 26 and 27 are formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof, and have the same external shape when they are viewed from the left and right sides, respectively. The left-hand aluminum plate 26, which partially constitutes the cool storage material container 14, includes a first swelled portion 28 for forming the container body 21, a second swelled portion 29 for forming the internal-volume-increasing portion 22, and third swelled portions 31 for forming the tank-forming portions 23. The first swelled portion 28 accounts for the greater part of the aluminum plate 26, excluding a front portion thereof, and is swelled leftward. The second swelled portion 29, which extends frontward from the first swelled portion 28, is swelled leftward, and has the same swelling height as the first swelled portion 28. The third swelled portions 31 are provided at the upper and lower ends of the second swelled portion 29, are swelled leftward, and have a swelling height greater than that of the second swelled portion 29. The above-mentioned communication holes 24 are formed on the swelled end walls of the third swelled portions 31 of the left and aluminum plate 26 of each cool storage material container 14, excluding the cool storage material container 14 at the left end.
The right-hand aluminum plate 27, which partially constitutes the cool storage material container 14, includes a flat portion 32 for forming the container body 21, a first swelled portion 33 for forming the internal-volume-increasing portion 22, and second swelled portions 34 for forming the tank-forming portions 23. The flat portion 32 accounts for the greater part of the aluminum plate 27, excluding a front portion thereof. The first swelled portion 33, which extends frontward from the flat portion 32, is swelled rightward. The second swelled portions 34 are provided at the upper and lower ends of the first swelled portion 33, are swelled rightward, and have a swelling height greater than that of the first swelled portion 33. The above-mentioned communication holes 24 are formed on the swelled end walls of the second swelled portions 34 of the right-hand aluminum plate 27 of each cool storage material container 14, excluding the cool storage material container 14 at the right end. The two aluminum plates 26 and 27 are assembled and brazed together so that the openings of the swelled portions 29 and 31 face the openings of the swelled portions 33 and 34, and the opening of the first swelled portion 28 is closed by the flat portion 32. Thus, the cool storage material container 14 is formed. The tank formation portions 23 of two adjacent cool storage material containers 14 are brazed to each other such that the communication holes 24 of the third swelled portions 31 communicate with the communication holes 24 of the second swelled portions 34.
A front portion of each corrugated fin 17 projects frontward from the front refrigerant flow tubes 13. A portion of the corrugated fin 17, which portion projects frontward from the front refrigerant flow tubes 13, is brazed to the left side surface of the internal-volume-increasing portion 22 of the cool storage material container 14 located on the right side of the corrugated fin 17, and is brazed to the right side surface of the internal-volume-increasing portion 22 of the cool storage material container 14 located on the left side of the corrugated fin 17.
As shown in FIG. 3, a container height Hc is the dimension (as measured in the thickness direction (left-right direction)) of the container body 21 of the cool storage material container 14 in thermal contact with the refrigerant flow tubes 13; i.e., the dimension of the cool storage material container 14, excluding the internal-volume-increasing portion 22. When the container height Hc is taken as 1, a tube height Ht, which is the dimension of the refrigerant flow tubes 13 as measured in the thickness direction (left-right direction), is set to 0.25 to 2.0, and a fin height Hf, which is the dimension of the corrugated fins 17 as measured in the direction of arrangement of the sets 15 each composed of the refrigerant flow tubes 13 and the cool storage material container 14 (left-right direction), is set to 1.0 to 5.5. In the case where the container height Hc of the container body 21 is set to 1, the tube height Ht of the refrigerant flow tubes 13 is set to 0.25 to 2.0, and the fin height Hf of the corrugated fins 17 is set to 1.0 to 5.5, it becomes possible to charge an appropriate amount of the cool storage material into each cool storage material container 14, to thereby effectively suppress an increase in the air passage resistance of the air-passing clearances and a decrease in the number of the refrigerant flow tubes 13, while preventing the cool storing time from increasing and preventing the cool releasing time from shortening when the compressor stops. Thus, it becomes possible to prevent a drop in cooling performance.
Specifically, there will be considered a case where a core length L of the heat exchange core section 4 (the distance between the outer edges of the corrugated fins 17 at the left and right ends; see FIG. 1) is 300 mm; a core height H (the vertical length of the corrugated fins 17, excluding the corrugated fins 17 at the left and right ends; see FIG. 1) is 250 mm; a core width W1 (the distance between the front edges of the front refrigerant flow tubes 13 and the rear edges of the rear refrigerant flow tubes 13; see FIG. 2) is 38 mm; a width of the refrigerant flow tubes 13 as measured in the front-rear direction is 17 mm; the thickness of the circumferential wall of each refrigerant flow tube 13 is 0.5 mm; and the thickness of each corrugated fin 17 is 0.1 mm. In such a case, the width W2 of each cool storage material container 14 as measured in the front-rear direction (see FIG. 2) is set to 50 mm; the container height Hc of the container body 21 of each cool storage material container 14 is set to 1.5 to 4 mm; the tube height Ht of each refrigerant flow tube 13 is set to 1 to 3 mm; and the fin height Hf of each corrugated fin 17 is set to 4 to 8 mm. When the container height Hc of the container body 21 is less than 1.5 mm, the amount of the cool storage material charged into all the cool storage material containers 14 becomes insufficient, and, when the compressor stops, the cool releasing time becomes short (see FIG. 7). When the container height Hc exceeds 4 mm, the area of the air-passing clearances 16 decreases, and the air passage resistance increases, whereby the cooling performance drops (see FIG. 8). In addition, when the container height Hc of the container body 21 exceeds 4 mm, the amount of the cool storage material charged into all the cool storage material containers 14 becomes excessive, and the cool storing time increases, whereby the performance of cooling down after start of cooling operation drops (see FIG. 9). Further, when the tube height Ht of each refrigerant flow tube 13 is less than 1 mm, a flow resistance acting on the refrigerant within the refrigerant flow tubes 13 increases, whereby the cooling performance drops. When the height Ht of each refrigerant flow tube 13 exceeds 3 mm, the area of the air-passing clearances 16 decreases, and the air passage-resistance increases, whereby the cooling performance drops (see FIG. 10). Further, when the fin height Hf of each corrugated fin 17 is less than 4 mm, the air passage resistance increases, whereby the cooling performance drops (see FIG. 11). When the fin height Hf of each corrugated fin 17 exceeds 8 mm, the number of the refrigerant flow tubes 13 decreases, whereby the cooling performance drops.
The above-described evaporator 1 with a cool storage function constitutes a refrigeration cycle using a fluorocarbon refrigerant, in combination with a compressor driven by an engine of a vehicle, a condenser (refrigerant cooler) for cooling the refrigerant discharged from the compressor, and an expansion valve (pressure-reducing unit) for reducing the pressure of the refrigerant having passed through the condenser. The refrigeration cycle is installed, as a car air conditioner, in a vehicle, such as an automobile, which temporarily stops the engine, which serves as a drive source of the compressor, when the vehicle is stopped. In the case of such an car air conditioner, when the compressor is operating, low pressure, two-phase refrigerant (a mixture of vapor refrigerant and liquid refrigerant) having been compressed by the compressor and having passed through the condenser and the expansion valve passes through the refrigerant inlet 7, and enters the inlet header section 5 of the evaporator 1. The refrigerant then passes through all the front refrigerant flow tubes 13, and enters the first intermediate header section 9. The refrigerant having entered the first intermediate header section 9 passes through the communication member 12, and enters the second intermediate header section 11. After that, the refrigerant passes through all the rear refrigerant flow tubes 13, enters the outlet header section 6, and flows out via the refrigerant outlet 8. When the refrigerant flows through the refrigerant flow tubes 13, the refrigerant performs heat exchange with air passing through the air-passing clearances 16, and flows out of the refrigerant flow tubes 13 in a vapor phase.
At that time, the cool storage material within the container body 21 of each cool storage material container 14 is cooled by the refrigerant flowing through the refrigerant flow tubes 13, and the cool storage material within the internal-volume-increasing portion 22 of each cool storage material container 14 is cooled by air having been cooled by the refrigerant while passing through the air-passing clearances 16. As a result, the cool storage material is frozen, whereby cool is stored therein.
When the compressor stops, the cool stored in the cool storage material within the container body 21 of each cool storage material container 14 is transferred from the left side surface of the container body 21 to air passing through the corresponding air-passing clearance 16 via the corrugated fin 17 brazed to the left side surface of the cool storage material container 14, and is also transferred from the right side surface of the container body 21 to air passing through the corresponding air-passing clearance 16 via the refrigerant flow tubes 13 and the corrugated fin 17 brazed to the refrigerant flow tubes 13. Further, the cool stored in the cool storage material within the internal-volume-increasing portion 22 of each cool storage material container 14 is transmitted from the left and right side surfaces of the internal-volume-increasing portion 22 to the air passing through the corresponding air-passing clearances 16 via the corrugated fins 17 brazed to the left and right side surfaces of the internal-volume-increasing portion 22. Accordingly, even when the temperature of wind having passed through the evaporator 1 increases, the wind is cooled, so that a sharp drop in the cooling capacity can be prevented.
FIG. 12 shows another embodiment of the evaporator with a cool storage function according to the present invention.
In the case of the evaporator with a cool storage function shown in FIG. 12, of the plurality of (two in the present embodiment) refrigerant flow tubes 13 and 40 arranged in the front-rear direction, the tube height (dimension in the thickness direction) of the refrigerant flow tubes 40 disposed on the front side (at the front end) is smaller than that of the refrigerant flow tubes 13 disposed on the rear side. Further, a front portion of each cool storage material container 41 does not project frontward from the front ends of the front refrigerant flow tubes 40, and an internal-volume-increasing portion 43 is provided at a portion of each cool storage material container 41, which portion is brazed to the corresponding refrigerant flow tube 40 having a small tube height. The container height (dimension in the thickness direction (left-right direction)) of an internal-volume-increasing portion 43 is greater than that of the remaining portion of the cool storage material container 41; i.e., that of a container body 42 located rearward of the rear edges of the front refrigerant flow tubes 40. The sum of the container height of the internal-volume-increasing portion 43 of the cool storage material container 41 and the tube height (dimension in the thickness direction) of the front refrigerant flow tube 40 is equal to the sum of the container height of the container body 42 of the cool storage material container 41 and the tube height (dimension in the thickness direction) of the rear refrigerant flow tube 13. Further, a front portion of each corrugated fin 17 does not project frontward from the front ends of the front refrigerant flow tubes 40. Each corrugated fin 17 is brazed to the right side surfaces of the refrigerant flow tubes 13 and 40 located on the left side of the corrugated fin 17, and is also brazed to the left side surfaces of the container body 42 and the internal-volume-increasing portion 43 of the cool storage material container 41 located on the right side of the corrugated fin 17.
In the above-described two embodiments, each of the refrigerant flow tube sections of the evaporator with a cool storage function may be provided in a flat hollow body formed, by two aluminum plates brazed together along their peripheral edge portions, as in the case of a so-called laminate-type evaporator. That is, each of the refrigerant flow tube sections may be formed between the two aluminum plates which were swelled so as to constitute a flat hollow body.
Further, in the above-described two embodiments, inner fins may be provided inside the cool storage material container.

Claims

1. An evaporator with a cool storage function comprising a plurality of flat refrigerant flow tube sections disposed such that their width direction coincides with an air flow direction and they are spaced from one another, and a plurality of flat cool storage material containers disposed such that their width direction coincides with the air flow direction, each of the cool storage material containers being in contact with one side surface of the corresponding refrigerant flow tube section and containing a cool storage material, wherein

an internal-volume-increasing portion is provided at an upstream or downstream portion of each cool storage material container with respect to the air flow direction, and has a container height greater than that of the remaining portion of the cool storage material container, the container height being a dimension in a thickness direction of the cool storage material container.

2. An evaporator with a cool storage function according to claim 1, wherein a plurality of sets each composed of a refrigerant flow tube section and a cool storage material container are disposed such that they are spaced from one another in a direction perpendicular to the width direction of the refrigerant flow tube sections; a space between adjacent sets each composed of a refrigerant flow tube section and a cool storage material container serves as an air-passing clearance; and a fin is disposed in the air-passing clearance, and is joined to the corresponding refrigerant flow tube section and the corresponding cool storage material container.

3. An evaporator with a cool storage function according to claim 2, wherein respective upstream or downstream portions of each cool storage material container and each fin project outward, with respect to the air flow direction, from the refrigerant flow tube sections; the internal-volume-increasing portion is provided at a portion of each cool storage material container, which portion projects outward, with respect to the air flow direction, from the refrigerant flow tube sections; and the fins are joined to opposite side surfaces of the internal-volume-increasing portion of each cool storage material container.

4. An evaporator with a cool storage function according to claim 3, wherein the interiors of the cool storage material containers communicate with one another at the internal-volume-increasing portions thereof.

5. An evaporator with a cool storage function according to claim 3, wherein respective downstream portions of each cool storage material container and each fin project downstream from the refrigerant flow tube sections; and the internal-volume-increasing portion is provided at a portion of each cool storage material container, which portion projects downstream from the refrigerant flow tube sections.

6. An evaporator with a cool storage function according to claim 2, wherein when the container height of each cool storage material container, excluding the internal-volume-increasing portion, is taken as 1, a tube section height, which is a dimension of each refrigerant flow tube section in a thickness direction thereof, is 0.25 to 2.0, and a fin height, which is a dimension of each fin in a direction of arrangement of the sets each composed of a refrigerant flow tube section and a cool storage material container, is 1.0 to 5.5.

7. An evaporator with a cool storage function according to claim 6, wherein the container height of each cool storage material container, excluding the internal-volume-increasing portion, is 1.5 to 4.0 mm, the tube section height of each refrigerant flow tube section is 1.0 to 3.0 mm, and the fin height is 4.0 to 8.0 mm.

8. An evaporator with a cool storage function according to claim 1, wherein a plurality of refrigerant flow tube sections are juxtaposed in the air flow direction; a tube section height of at least the refrigerant flow tube section disposed on the downstream end, the tube section height being a dimension in the thickness direction thereof, is smaller than that of the remaining refrigerant flow tube section(s); and the internal-volume-increasing portion is provided at a portion of each cool storage material container, which portion is in contact with the refrigerant flow tube section having the smaller tube section height.