CA1334796C - Condenser - Google Patents
CondenserInfo
- Publication number
- CA1334796C CA1334796C CA000601106A CA601106A CA1334796C CA 1334796 C CA1334796 C CA 1334796C CA 000601106 A CA000601106 A CA 000601106A CA 601106 A CA601106 A CA 601106A CA 1334796 C CA1334796 C CA 1334796C
- Authority
- CA
- Canada
- Prior art keywords
- condenser
- coolant
- cooling medium
- height
- header
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/0202—Header boxes having their inner space divided by partitions
- F28F9/0204—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions
- F28F9/0209—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions having only transversal partitions
- F28F9/0212—Header boxes having their inner space divided by partitions for elongated header box, e.g. with transversal and longitudinal partitions having only transversal partitions the partitions being separate elements attached to header boxes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B39/00—Evaporators; Condensers
- F25B39/04—Condensers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/02—Tubular elements of cross-section which is non-circular
- F28F1/022—Tubular elements of cross-section which is non-circular with multiple channels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/02—Header boxes; End plates
- F28F9/0243—Header boxes having a circular cross-section
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
- F28D2021/008—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for vehicles
- F28D2021/0084—Condensers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F2255/00—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes
- F28F2255/16—Heat exchanger elements made of materials having special features or resulting from particular manufacturing processes extruded
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Geometry (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
- Valve Device For Special Equipments (AREA)
- Oscillators With Electromechanical Resonators (AREA)
- Vending Machines For Individual Products (AREA)
- Air-Conditioning For Vehicles (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
Abstract
A condenser particularly for use in automobile air conditioning system, the condenser including a pair of headers having their inner spaces divided by partitions so as to form a cooling medium flow path in a zigzag patterns including an inlet side group of paths and an outlet side group of paths, side group of paths is 30 to 60% of that of the inlet side group of paths.
Description
The present invention relates to a condenser particularly adapted for use in automobile air conditioning system.
For such use, a "serpentine" type of condenser is well known and widely used, which is made up of a multi-bored flat tube, commonly called "harmonica" tube, bent in zigzag form, and corrugated fins sandwiched between the bent tube walls.
In this way a core is constituted.
The cooling medium path in a condenser is roughly classified into two sections, that is, an inlet side section and an outlet side section. In the inlet side section the cooling medium is still in a gaseous state, and in the outlet side section it becomes liquid. In order to increase the efficiency of heat ~YchAnge the area for heat exchange of the inlet side paths should be as large as possible. On the other hand, that of the outlet side paths can be relatively small.
Since the "serpentine" type condenser consists of a single cooling medium path provided by a single pipe, an increase in the area for heat exchange in the inlet side section increases that of the outlet side section. As a whole the size of the condenser become large.
The inventors have made an invention relating to a "multi-flow" type condenser instead of the serpentine type, which is disclosed in Japanese Patent Publication (unexamined) No. 63-34466. The multi-flow type condenser includes a plurality of tubes arranged in parallel and heat releasing means, e.g., corrugated fins sandwiched S therebetween, and headers connected to opposite ends of the tubes. The headers have partitions which divide their inner spaces into at least two sections including an inlet side group of paths and an outlet side group of paths, thereby causing the cooling medium to flow in at least one zigzag pattern. The total cross-sectional area of the inlet side group of paths progressively dimi ni shes toward the outlet side group. In this way the inlet side section has an optimum area for accommodating the cooling medium in a gaseous state, and the outlet side section has an optimum area for accommodating that in a liquid state. Thus the multi-flow type condenser has succeeded in reducing the size of condensers without trading off the efficiency of heat exchange. However, one problem arises in what proportion the whole path is divided into the gaseous phase side (i.e. the inlet side section) and the liquid phase side (i.e. the outlet side section) by partitions. The improper proportion unfavorably affects the efficiency of heat exchange and causes pressure loss on the flow of the cooling medium.
If the area in the outlet side section is insufficiently reduced as compared with that of the inlet side section, it becomes difficult to secure a sufficiently increased cross-sectional area of the inlet side section. As a result the cooling medium undergoes a larger pressure loss, and the efficiency of heat exchange decreases because of the relatively small area for heat exchange. If, however, the area in the outlet side section is excessively reduced as compared with that of the inlet side section, pressure loss is likely to increase on the flow of the cooling medium. The area for heat exchange of the inlet side section becomes too large, thereby slowing down the flow rate of the cooling medium.
Accordingly, the present invention provides a condenser having cooling medium paths divided in an inlet side section and an outlet side section in an optimum proportion, thereby lS increasing the efficiency of heat exchange and reducing the pressure loss of a cooling medium.
In one aspect, the invention provides a condenser for liquifying gaseous coolant in an air conditioning system of an automobile after the system has compressed the coolant, said condenser comprising:
, (i) a plurality of flat tubular elements defining flow paths and disposed in a spaced, substantially parallel relation, each element including at least one inside wall;
(ii) a plurality of fin members, each fin member disposed between adjacent tubular elements;
(iii) a pair of headers disposed in a spaced, substantially parallel relation at opposite ends of the tubular elements, the one and/or the other header defining a coolant inlet and a coolant outlet for the condenser, each header being an elongate member and defining, for each tubular element, an opening through which it receives the tubular element and establishes fluid communication with the element;
(iv) at least one partitioning plate mounted in one of the headers transversely of the header to divide the inside opening of the header;
the coolant flowing from the inlet into one header and making a first pass through a plurality of the tubes to the other header, the coolant also making a final pass through a plurality of tubes to the outlet,-the tubular elements and headers forming a first zone which receives gaseous coolant from the inlet and a final zone through which the coolant flows before discharging through the outlet, the effective cross-sectional area of the flow paths defined by the tubular elements through which the coolant makes the final pass being D-~q~
30% - ~ of the effective cross-sectional area of the flow paths of those through which the coolant makes the first pass; said condenser being able to resist internal pressures greater than 10 atmospheres.
This invention will be further illustrated by way of the accompanying drawings, in which:
Fig. 1 is a plan view of a condenser according to the present invention;
Fig. 2 is a cross-sectional view on an enlarged scale taken along the line II II of Fig. l;
Fig. 3 is an exploded perspective view of the - 4a -condenser of ~ig. 1;
Fig. 4 i8 a fragmentary cross-sectional view on an enlarged scale showing the flat tube and the corrugated fin when observed in the same direction as in Fig. 3;
Fig. 5 is a fragmentary front view showing a relationship between the corrugated fins and the flat tubes;
Fig. 6 is a diagrammatic view showing flow patterns of a coolant medium;
Fig. 7 is a graph showing a relationship between the ratios of cross-~ectional area of the outlet side section to the inlet side section and the rate of heat exchange;
Fig. 8 is a graph showing a relationship between the ratios of cross-sectional area of the outlet side section to the inlet side section and the pressure 1088 on the cooling medium;
Fig. 9 i8 a graph showing a relationship between the number of cooling medium paths and the rate of heat exchange;
Fig. 10 is a graph showing a relationship between the number of cooling medium paths and the pressure 1088 on the cooling medium;
Fig. 11 is a graph showing a relationship between the number of cooling medium paths, the rate of heat exchange and the pressure 1088 on the cooling medium;
Fig. 12 is a graph showing a relationship between the widths of flat tubes and the rate of heat transfer;
Fig. 13 is a graph showing a relationship between the heights of flat tubes and the pneumatic pressure loss;
Fig. 14 is a graph showing relationships between the rate of heat exchange and the heights of corrugated fins, and between the pneumatic pressure loss and the heights of corrugated fins; and Fig. 15 is a graph showing relationships between the rate of heat exchange and the pitches of corrugated fins, and between the pneumatic pressure loss and the pitches of corrugated fins.
Referring to Figs. 1 to 6, the illustrated condenser includes a plurality of flat tubes 1 stacked in parallel and corrugated fins 2 sandwiched between the flat tubes 1. The terminating ends of the flat tubes 1 are connected to headers 3 and 4.
Each flat tube is made of extruded aluminum, having a flat configuration as clearly shown in Figs. 2 to 4.
Alternatively, the flat tubes can be multibored flat tubes, commonly called "harmonic tube" or else, electrically seamed tubes can be used.
Each corrugated fin 2 has a width identical with that of the flat tube 1. The fins 2 and the flat ~q X:
tubes 1 are braæed to each other. Preferably the fins 2 are provided with louvers 2a on the surface.
The headers 3, 4 are made up of electrically seamed pipes of aluminum, and each have holes 5 of the same shape as the cross-section of the flat tubes 1 80 as to accept the tube ends la. The inserted tube ends la are brazed in the holes 5. As shown in Fig. 1, the headers 3 and 4 are connected to an inlet pipe 6 and an outlet pipe 7, respectively. The inlet pipe 6 allows a cooling medium to enter the header 3, and the outlet pipe 8 allows the used cooling medium to discharge. The headers 3 and 4 are closed with covers 7 and 9, respectively. The reference numerals 13 and 14 denote side places attached to the outermost corrugated fins 2.
The header 3 has its inner space divided by a partition 10 into two ~ections, and the header 4 also has two sections divided by a partition 11. In this way the whole cooling medium path 12 is divided into an inlet side group (A), an intermediate group (B) and an outlet side group (C) as shown Figs. 1 and 6. The cooling medium flows in zigzag patterns throughout the groups (A), (B) and (C). As shown in Fig. 6, it is arranged that the intermediate group (B) has a smaller number of flat tubes 1 (that is, paths) than the inlet side group (A), which means that the cross-sectional area of the intermediate group (C) of paths is smaller than that of the group (A). It is al80 arranged that the outlet si~e gr-oup (C) has a smaller number of flat tubes 1 (that is, the number of cooling medium paths) than the intermediate group (B), which means that the cross-sectional area of the outlet side group (C) of paths is smaller than that of the group (B).
In terms of percentage the entire cross-sectional area of the outlet side group (C) is 30 to 60% of that of the inlet side group (A). If the percentage is less than 30%, the cross-sectional area of the outlet side group (C) becomes small to increase the pressure 1088 in the cooling medium. At the same time, the cross-sectional area of the inlet side group becomes large to slow down the flow rate of the cooling medium, thereby reducing the efficiency of heat exchange. If the percentage exceeds 60%, the cross-sectional area of the inlet side group (A) becomes small to increase the pressure 1088 in the cooling medium. In addition, the area for heat transfer is reduced, thereby reducing the efficiency of heat exchange. It is more preferred that the entire cross-sectional area of the outlet side group (C) is 35 to 50% of that of the inlet side group (A). As shown in Figs. 7 and 8, this more restricted range exhibits the highest efficiency of heat exchange and the lowest pressure 1088 in the cooling medium.
As shown in Fig. 6, the cooling medium is introduced into the inlet side group (A) through the inlet pipe 6 and flows therethrough. Then the cooling medium turns from the right-hand header 4 and enters the intermediate group (B). Then it turns from the left-hand header 3 and enters the outlet side group (C). Finally the cooling medium i8 discharged through the outlet pipe 8. In this way the cooling medium flows in zigzag patterns. Air enters the air paths constituted by the corrugated fins 2 in the direction (W) in Fig. 2. Heat exchange is effected between the air and the cooling medium flowing through the groups (A), (B) and (C). While the cooling medium passes through the inlet ~ide group (A), it is still in a gaseous state and has a relatively large volume, which is effectively accommodated in the capacity provided by the paths of the group (A) and keeps contact with the flat tubes 1 in a wide range 80 that the gaseous cooling medium smoothly condenses and reduces its volume. When the cooling medium flows through the outlet side group by way of the intermediate group (B), it becomes completely liquid, and has such a reduced volume as to be accommodated in a relatively small cross-sectional area of the outlet side group (C). Thus the pressure 1088 is minimized, thereby enhancing the efficiency of heat exchange.
The illustrated embodiment has three groups (A), (B) and (C), but the number (N) of groups is not limited to it. Preferably the number (N) is 2 to 5 groups for the reason explained below: ^
Figs. 9 to 11 show the results obtained by experiments i~ which condensers having twenty-four flat tubes are employed, each having a different number of groups. A cooling medium is introduced into each of the condensers at the same flow rate. Each graph shows the resulting rate of heat exchange and pressure 1088 in the cooling medium, and changes in the rate of heat exchangè and pressure 1088 with respect to the ratio of the outlet side group to the inlet side group. Throughout the experiments the inlet side group, the intermediate group and the outlet ~ide group have the same cross-sectional area.
Fig. 9 shows the rates of heat exchange achieved when the speed of wind Vf i8 2m/sec and when it is 3m/sec each in front of the condenser. It will be understood from Fig. 9 that when the number (N) of the groups is less than 2 the rate of heat exchange is low, whereas when it exceeds five, the rate of heat exchange gradually diminishes. It will be understood from Fig.
10 that as the number (N) of groups increases, the pressure 1088 in the cooling medium increases, especially when the number (N) exceeds five, it abruptly increases. It will be understood from Fig.
11 that if the number (N) of the groups is less than two, the pressure loss is low but the rate of heat exchange is also low. Therefore the ratio of the rate of heat exchange to the pressure 1088 becomes low, which indicates that there is an imbalance between the pressure 1088 and the rate of heat exchange. If the number (N) of the ~roups exceeds five, the rate of heat exchange becomes relatively high but the pressure 1088 becomes low. The ratio between them is low, thereby causing an imbalance between the pressure 1088 and the rate of heat exchange.
As is evident from the results of the experiments, when the number (N) of the groups is 2 to 5, the rate of heat exchange is high, and the pressure 1088 in the cooling medium is low. Thus the ratio between them is well balanced. As described above, it is arranged to ensure that the cross-sectional area of the outlet side group (C) is arranged to have 30 to 60% of that of the inlet side group (A). In addition, the number (N) of the group is arranged to be 2 to 5, which enhances the efficiency of the heat exchange as a result of the reduced pressure 1088.
It is preferred that the width (Wt) of each flat tube 1 is in the range of 6.0 to 20mm, the height (Ht) thereof is in the range of 1.5 to 7.Omm, the height (Hp) of the cooling medium paths 12 in the flat tubes 1 is l.Omm or more. It is also arranged that the height (Hf) of the corrugated fins 2 or a distance between the adjacent flat tubes 1 is in the range-of 6 to 16mm and that the fin pitch (Fp) is in the range of 1.6 to 4.Omm. The reasons why the above-mentioned ranges are preferable will be described below:
As is evident from Fig. 12, if the width (Wt) of the flat tubes 1 is less than 6.Omm, the corrugated fins 2 sandwiched ,therebetween will be accordingly narrow in width. The narrow width of the corrugated fins 2 limit the size and number of the louvers 2a, which decreases the efficiency of heat exchange. If the flat tubes 1 are 20mm or more, the corrugated fin~
2 sandwiched therebetween will accordingly become large. The large fins increases a drag on the flowing air. In addition, the large fins increases the weight of the condenser. It is therefore preferred that the width (Wt) of the flat tubes is in the range of 6.0 to 16mm, more preferably, 10 to 14mm.
The height (Ht) of each flat tube 1 is preferably in the range of 1.5 to 7.Omm. If it exceeds 7.Omm, the pressure 1088 in the air flow increases. If it is less than 1.5mm, it is difficult to increase the height (Hp) of the air paths by l.Omm or more because of the limited thickness of the flat tubes. It is preferred that it is in the range of 1.5 to 5.Omm;
more preferably, 2.5to 4.Omm.
The height (Hp) of the cooling medium flow paths in the flat tubes 1 is preferably l.Omm or more. If it is less than l.Omm, the pressure 1088 in the cooling medium increases, thereby decreasing the rates of heat transfer. It i8 preferred that it is in the range of 1.5 to 2.Omm.
The height (Hf) of the corrugated fins 2 is in the range of 6.0 to 16mm. If it is less than 6mm, the pressure 1088 in the air will increase as shown in Fig. 14. If it exceeds 16mm, the number of total fins decreases, thereby reducing the efficiency of heat exchange. The optimum range is 8.0 to 12mm.
As shown in Fig. 15, the fin pitches is preferably in the range of 1.6 to 4.Omm. If they are less than 1.6mm, the louvers 2a interfere with the flow of the air, thereby increasing the pressure 1088 in the air flow. If they exceed 4.Omm, the efficiency of heat exchange decreases. It is therefore preferred that the range is 1.6 to 3.2mm; more preferably, 2.0 to 3.2mm.
As i8 evident from the foregoing description, the condensers of the present invention are constructed with the flat tubes, the corrugated fins and the headers in which the widths and heights of the flat tubes, the heights of the cooling medium flow paths, the heights and pitches of the fin are determined at optimum values, thereby reducing the pressure losses which the air and the cooling medium undergo. As a result the efficiency of heat exchanger is enhanced.
In the illustrated embodiment the cross-sectional area of the cooling medium paths 12 progressively diminishes from the inlet side group to the outlet side group through the intermediate group. However it is possible to modify it to an embodiment in which the inlet side group and the intermediate group have the same cross-sectional area which is larger than that of the outlet side gr~up. In the illustrated embodiment the reduction in the cross-sectional area is effected by reducing the number of the flat tubes, but it is possible to reduce the cross-sectional areas of the individual flat tubes without changing the number thereof. The header~ 3 and 4 are provided at their erected posture~ between which the flat tubes 1 are horizontally stacked one above another, but it is possible to modify it to an embodiment in which the headers 3 and 4 are po~itioned up and down between which the flat tubes are vertically arranged in parallel.
For such use, a "serpentine" type of condenser is well known and widely used, which is made up of a multi-bored flat tube, commonly called "harmonica" tube, bent in zigzag form, and corrugated fins sandwiched between the bent tube walls.
In this way a core is constituted.
The cooling medium path in a condenser is roughly classified into two sections, that is, an inlet side section and an outlet side section. In the inlet side section the cooling medium is still in a gaseous state, and in the outlet side section it becomes liquid. In order to increase the efficiency of heat ~YchAnge the area for heat exchange of the inlet side paths should be as large as possible. On the other hand, that of the outlet side paths can be relatively small.
Since the "serpentine" type condenser consists of a single cooling medium path provided by a single pipe, an increase in the area for heat exchange in the inlet side section increases that of the outlet side section. As a whole the size of the condenser become large.
The inventors have made an invention relating to a "multi-flow" type condenser instead of the serpentine type, which is disclosed in Japanese Patent Publication (unexamined) No. 63-34466. The multi-flow type condenser includes a plurality of tubes arranged in parallel and heat releasing means, e.g., corrugated fins sandwiched S therebetween, and headers connected to opposite ends of the tubes. The headers have partitions which divide their inner spaces into at least two sections including an inlet side group of paths and an outlet side group of paths, thereby causing the cooling medium to flow in at least one zigzag pattern. The total cross-sectional area of the inlet side group of paths progressively dimi ni shes toward the outlet side group. In this way the inlet side section has an optimum area for accommodating the cooling medium in a gaseous state, and the outlet side section has an optimum area for accommodating that in a liquid state. Thus the multi-flow type condenser has succeeded in reducing the size of condensers without trading off the efficiency of heat exchange. However, one problem arises in what proportion the whole path is divided into the gaseous phase side (i.e. the inlet side section) and the liquid phase side (i.e. the outlet side section) by partitions. The improper proportion unfavorably affects the efficiency of heat exchange and causes pressure loss on the flow of the cooling medium.
If the area in the outlet side section is insufficiently reduced as compared with that of the inlet side section, it becomes difficult to secure a sufficiently increased cross-sectional area of the inlet side section. As a result the cooling medium undergoes a larger pressure loss, and the efficiency of heat exchange decreases because of the relatively small area for heat exchange. If, however, the area in the outlet side section is excessively reduced as compared with that of the inlet side section, pressure loss is likely to increase on the flow of the cooling medium. The area for heat exchange of the inlet side section becomes too large, thereby slowing down the flow rate of the cooling medium.
Accordingly, the present invention provides a condenser having cooling medium paths divided in an inlet side section and an outlet side section in an optimum proportion, thereby lS increasing the efficiency of heat exchange and reducing the pressure loss of a cooling medium.
In one aspect, the invention provides a condenser for liquifying gaseous coolant in an air conditioning system of an automobile after the system has compressed the coolant, said condenser comprising:
, (i) a plurality of flat tubular elements defining flow paths and disposed in a spaced, substantially parallel relation, each element including at least one inside wall;
(ii) a plurality of fin members, each fin member disposed between adjacent tubular elements;
(iii) a pair of headers disposed in a spaced, substantially parallel relation at opposite ends of the tubular elements, the one and/or the other header defining a coolant inlet and a coolant outlet for the condenser, each header being an elongate member and defining, for each tubular element, an opening through which it receives the tubular element and establishes fluid communication with the element;
(iv) at least one partitioning plate mounted in one of the headers transversely of the header to divide the inside opening of the header;
the coolant flowing from the inlet into one header and making a first pass through a plurality of the tubes to the other header, the coolant also making a final pass through a plurality of tubes to the outlet,-the tubular elements and headers forming a first zone which receives gaseous coolant from the inlet and a final zone through which the coolant flows before discharging through the outlet, the effective cross-sectional area of the flow paths defined by the tubular elements through which the coolant makes the final pass being D-~q~
30% - ~ of the effective cross-sectional area of the flow paths of those through which the coolant makes the first pass; said condenser being able to resist internal pressures greater than 10 atmospheres.
This invention will be further illustrated by way of the accompanying drawings, in which:
Fig. 1 is a plan view of a condenser according to the present invention;
Fig. 2 is a cross-sectional view on an enlarged scale taken along the line II II of Fig. l;
Fig. 3 is an exploded perspective view of the - 4a -condenser of ~ig. 1;
Fig. 4 i8 a fragmentary cross-sectional view on an enlarged scale showing the flat tube and the corrugated fin when observed in the same direction as in Fig. 3;
Fig. 5 is a fragmentary front view showing a relationship between the corrugated fins and the flat tubes;
Fig. 6 is a diagrammatic view showing flow patterns of a coolant medium;
Fig. 7 is a graph showing a relationship between the ratios of cross-~ectional area of the outlet side section to the inlet side section and the rate of heat exchange;
Fig. 8 is a graph showing a relationship between the ratios of cross-sectional area of the outlet side section to the inlet side section and the pressure 1088 on the cooling medium;
Fig. 9 i8 a graph showing a relationship between the number of cooling medium paths and the rate of heat exchange;
Fig. 10 is a graph showing a relationship between the number of cooling medium paths and the pressure 1088 on the cooling medium;
Fig. 11 is a graph showing a relationship between the number of cooling medium paths, the rate of heat exchange and the pressure 1088 on the cooling medium;
Fig. 12 is a graph showing a relationship between the widths of flat tubes and the rate of heat transfer;
Fig. 13 is a graph showing a relationship between the heights of flat tubes and the pneumatic pressure loss;
Fig. 14 is a graph showing relationships between the rate of heat exchange and the heights of corrugated fins, and between the pneumatic pressure loss and the heights of corrugated fins; and Fig. 15 is a graph showing relationships between the rate of heat exchange and the pitches of corrugated fins, and between the pneumatic pressure loss and the pitches of corrugated fins.
Referring to Figs. 1 to 6, the illustrated condenser includes a plurality of flat tubes 1 stacked in parallel and corrugated fins 2 sandwiched between the flat tubes 1. The terminating ends of the flat tubes 1 are connected to headers 3 and 4.
Each flat tube is made of extruded aluminum, having a flat configuration as clearly shown in Figs. 2 to 4.
Alternatively, the flat tubes can be multibored flat tubes, commonly called "harmonic tube" or else, electrically seamed tubes can be used.
Each corrugated fin 2 has a width identical with that of the flat tube 1. The fins 2 and the flat ~q X:
tubes 1 are braæed to each other. Preferably the fins 2 are provided with louvers 2a on the surface.
The headers 3, 4 are made up of electrically seamed pipes of aluminum, and each have holes 5 of the same shape as the cross-section of the flat tubes 1 80 as to accept the tube ends la. The inserted tube ends la are brazed in the holes 5. As shown in Fig. 1, the headers 3 and 4 are connected to an inlet pipe 6 and an outlet pipe 7, respectively. The inlet pipe 6 allows a cooling medium to enter the header 3, and the outlet pipe 8 allows the used cooling medium to discharge. The headers 3 and 4 are closed with covers 7 and 9, respectively. The reference numerals 13 and 14 denote side places attached to the outermost corrugated fins 2.
The header 3 has its inner space divided by a partition 10 into two ~ections, and the header 4 also has two sections divided by a partition 11. In this way the whole cooling medium path 12 is divided into an inlet side group (A), an intermediate group (B) and an outlet side group (C) as shown Figs. 1 and 6. The cooling medium flows in zigzag patterns throughout the groups (A), (B) and (C). As shown in Fig. 6, it is arranged that the intermediate group (B) has a smaller number of flat tubes 1 (that is, paths) than the inlet side group (A), which means that the cross-sectional area of the intermediate group (C) of paths is smaller than that of the group (A). It is al80 arranged that the outlet si~e gr-oup (C) has a smaller number of flat tubes 1 (that is, the number of cooling medium paths) than the intermediate group (B), which means that the cross-sectional area of the outlet side group (C) of paths is smaller than that of the group (B).
In terms of percentage the entire cross-sectional area of the outlet side group (C) is 30 to 60% of that of the inlet side group (A). If the percentage is less than 30%, the cross-sectional area of the outlet side group (C) becomes small to increase the pressure 1088 in the cooling medium. At the same time, the cross-sectional area of the inlet side group becomes large to slow down the flow rate of the cooling medium, thereby reducing the efficiency of heat exchange. If the percentage exceeds 60%, the cross-sectional area of the inlet side group (A) becomes small to increase the pressure 1088 in the cooling medium. In addition, the area for heat transfer is reduced, thereby reducing the efficiency of heat exchange. It is more preferred that the entire cross-sectional area of the outlet side group (C) is 35 to 50% of that of the inlet side group (A). As shown in Figs. 7 and 8, this more restricted range exhibits the highest efficiency of heat exchange and the lowest pressure 1088 in the cooling medium.
As shown in Fig. 6, the cooling medium is introduced into the inlet side group (A) through the inlet pipe 6 and flows therethrough. Then the cooling medium turns from the right-hand header 4 and enters the intermediate group (B). Then it turns from the left-hand header 3 and enters the outlet side group (C). Finally the cooling medium i8 discharged through the outlet pipe 8. In this way the cooling medium flows in zigzag patterns. Air enters the air paths constituted by the corrugated fins 2 in the direction (W) in Fig. 2. Heat exchange is effected between the air and the cooling medium flowing through the groups (A), (B) and (C). While the cooling medium passes through the inlet ~ide group (A), it is still in a gaseous state and has a relatively large volume, which is effectively accommodated in the capacity provided by the paths of the group (A) and keeps contact with the flat tubes 1 in a wide range 80 that the gaseous cooling medium smoothly condenses and reduces its volume. When the cooling medium flows through the outlet side group by way of the intermediate group (B), it becomes completely liquid, and has such a reduced volume as to be accommodated in a relatively small cross-sectional area of the outlet side group (C). Thus the pressure 1088 is minimized, thereby enhancing the efficiency of heat exchange.
The illustrated embodiment has three groups (A), (B) and (C), but the number (N) of groups is not limited to it. Preferably the number (N) is 2 to 5 groups for the reason explained below: ^
Figs. 9 to 11 show the results obtained by experiments i~ which condensers having twenty-four flat tubes are employed, each having a different number of groups. A cooling medium is introduced into each of the condensers at the same flow rate. Each graph shows the resulting rate of heat exchange and pressure 1088 in the cooling medium, and changes in the rate of heat exchangè and pressure 1088 with respect to the ratio of the outlet side group to the inlet side group. Throughout the experiments the inlet side group, the intermediate group and the outlet ~ide group have the same cross-sectional area.
Fig. 9 shows the rates of heat exchange achieved when the speed of wind Vf i8 2m/sec and when it is 3m/sec each in front of the condenser. It will be understood from Fig. 9 that when the number (N) of the groups is less than 2 the rate of heat exchange is low, whereas when it exceeds five, the rate of heat exchange gradually diminishes. It will be understood from Fig.
10 that as the number (N) of groups increases, the pressure 1088 in the cooling medium increases, especially when the number (N) exceeds five, it abruptly increases. It will be understood from Fig.
11 that if the number (N) of the groups is less than two, the pressure loss is low but the rate of heat exchange is also low. Therefore the ratio of the rate of heat exchange to the pressure 1088 becomes low, which indicates that there is an imbalance between the pressure 1088 and the rate of heat exchange. If the number (N) of the ~roups exceeds five, the rate of heat exchange becomes relatively high but the pressure 1088 becomes low. The ratio between them is low, thereby causing an imbalance between the pressure 1088 and the rate of heat exchange.
As is evident from the results of the experiments, when the number (N) of the groups is 2 to 5, the rate of heat exchange is high, and the pressure 1088 in the cooling medium is low. Thus the ratio between them is well balanced. As described above, it is arranged to ensure that the cross-sectional area of the outlet side group (C) is arranged to have 30 to 60% of that of the inlet side group (A). In addition, the number (N) of the group is arranged to be 2 to 5, which enhances the efficiency of the heat exchange as a result of the reduced pressure 1088.
It is preferred that the width (Wt) of each flat tube 1 is in the range of 6.0 to 20mm, the height (Ht) thereof is in the range of 1.5 to 7.Omm, the height (Hp) of the cooling medium paths 12 in the flat tubes 1 is l.Omm or more. It is also arranged that the height (Hf) of the corrugated fins 2 or a distance between the adjacent flat tubes 1 is in the range-of 6 to 16mm and that the fin pitch (Fp) is in the range of 1.6 to 4.Omm. The reasons why the above-mentioned ranges are preferable will be described below:
As is evident from Fig. 12, if the width (Wt) of the flat tubes 1 is less than 6.Omm, the corrugated fins 2 sandwiched ,therebetween will be accordingly narrow in width. The narrow width of the corrugated fins 2 limit the size and number of the louvers 2a, which decreases the efficiency of heat exchange. If the flat tubes 1 are 20mm or more, the corrugated fin~
2 sandwiched therebetween will accordingly become large. The large fins increases a drag on the flowing air. In addition, the large fins increases the weight of the condenser. It is therefore preferred that the width (Wt) of the flat tubes is in the range of 6.0 to 16mm, more preferably, 10 to 14mm.
The height (Ht) of each flat tube 1 is preferably in the range of 1.5 to 7.Omm. If it exceeds 7.Omm, the pressure 1088 in the air flow increases. If it is less than 1.5mm, it is difficult to increase the height (Hp) of the air paths by l.Omm or more because of the limited thickness of the flat tubes. It is preferred that it is in the range of 1.5 to 5.Omm;
more preferably, 2.5to 4.Omm.
The height (Hp) of the cooling medium flow paths in the flat tubes 1 is preferably l.Omm or more. If it is less than l.Omm, the pressure 1088 in the cooling medium increases, thereby decreasing the rates of heat transfer. It i8 preferred that it is in the range of 1.5 to 2.Omm.
The height (Hf) of the corrugated fins 2 is in the range of 6.0 to 16mm. If it is less than 6mm, the pressure 1088 in the air will increase as shown in Fig. 14. If it exceeds 16mm, the number of total fins decreases, thereby reducing the efficiency of heat exchange. The optimum range is 8.0 to 12mm.
As shown in Fig. 15, the fin pitches is preferably in the range of 1.6 to 4.Omm. If they are less than 1.6mm, the louvers 2a interfere with the flow of the air, thereby increasing the pressure 1088 in the air flow. If they exceed 4.Omm, the efficiency of heat exchange decreases. It is therefore preferred that the range is 1.6 to 3.2mm; more preferably, 2.0 to 3.2mm.
As i8 evident from the foregoing description, the condensers of the present invention are constructed with the flat tubes, the corrugated fins and the headers in which the widths and heights of the flat tubes, the heights of the cooling medium flow paths, the heights and pitches of the fin are determined at optimum values, thereby reducing the pressure losses which the air and the cooling medium undergo. As a result the efficiency of heat exchanger is enhanced.
In the illustrated embodiment the cross-sectional area of the cooling medium paths 12 progressively diminishes from the inlet side group to the outlet side group through the intermediate group. However it is possible to modify it to an embodiment in which the inlet side group and the intermediate group have the same cross-sectional area which is larger than that of the outlet side gr~up. In the illustrated embodiment the reduction in the cross-sectional area is effected by reducing the number of the flat tubes, but it is possible to reduce the cross-sectional areas of the individual flat tubes without changing the number thereof. The header~ 3 and 4 are provided at their erected posture~ between which the flat tubes 1 are horizontally stacked one above another, but it is possible to modify it to an embodiment in which the headers 3 and 4 are po~itioned up and down between which the flat tubes are vertically arranged in parallel.
Claims (8)
1. A condenser for liquifying gaseous coolant in an air conditioning system of an automobile after the system has compressed the coolant, said condenser comprising:
(i) a plurality of flat tubular elements defining flow paths and disposed in a spaced, substantially parallel relation, each element including at least one inside wall;
(ii) a plurality of fin members, each fin member disposed between adjacent tubular elements;
(iii) a pair of headers disposed in a spaced, substantially parallel relation at opposite ends of the tubular elements, the one and/or the other header defining a coolant inlet and a coolant outlet for the condenser, each header being an elongate member and defining, for each tubular element, an opening through which it receives the tubular element and establishes fluid communication with the element;
(iv) at least one partitioning plate mounted in one of the headers transversely of the header to divide the inside opening of the header;
the coolant flowing from the inlet into one header and making a first pass through a plurality of the tubes to the other header, the coolant also making a final pass through a plurality of tubes to the outlet, the tubular elements and headers forming a first zone which receives gaseous coolant from the inlet and a final zone through which the coolant flows before discharging through the outlet, the effective cross-sectional area of the flow paths defined by the tubular elements through which the coolant makes the final pass being 30% - 60% of the effective cross-sectional area of the flow paths of those through which the coolant makes the first pass; said condenser being able to resist internal pressures greater than 10 atmospheres.
(i) a plurality of flat tubular elements defining flow paths and disposed in a spaced, substantially parallel relation, each element including at least one inside wall;
(ii) a plurality of fin members, each fin member disposed between adjacent tubular elements;
(iii) a pair of headers disposed in a spaced, substantially parallel relation at opposite ends of the tubular elements, the one and/or the other header defining a coolant inlet and a coolant outlet for the condenser, each header being an elongate member and defining, for each tubular element, an opening through which it receives the tubular element and establishes fluid communication with the element;
(iv) at least one partitioning plate mounted in one of the headers transversely of the header to divide the inside opening of the header;
the coolant flowing from the inlet into one header and making a first pass through a plurality of the tubes to the other header, the coolant also making a final pass through a plurality of tubes to the outlet, the tubular elements and headers forming a first zone which receives gaseous coolant from the inlet and a final zone through which the coolant flows before discharging through the outlet, the effective cross-sectional area of the flow paths defined by the tubular elements through which the coolant makes the final pass being 30% - 60% of the effective cross-sectional area of the flow paths of those through which the coolant makes the first pass; said condenser being able to resist internal pressures greater than 10 atmospheres.
2. A condenser as defined in claim 1, wherein the effective cross-sectional area of the flow paths defined by the tubular elements through which the coolant makes the final pass is 35% - 50% the effective cross-sectional area of the flow paths of those through which the coolant makes the first pass.
3. A condenser as defined in claim 1, further comprising one to three intermediate groups of cooling medium paths between the inlet side group and the outlet side group.
4. A condenser as defined in claim 1, wherein each flat tubular element has the following dimensions:
width : 6.0 to 20 mm height : 1.5 to 7.0 mm height of each cooling medium flow path : 1.0 mm or more the fin members being corrugated fins which have the following dimensions:
height : 6.0 to 16 mm fin pitch : 1.6 to 4.0 mm
width : 6.0 to 20 mm height : 1.5 to 7.0 mm height of each cooling medium flow path : 1.0 mm or more the fin members being corrugated fins which have the following dimensions:
height : 6.0 to 16 mm fin pitch : 1.6 to 4.0 mm
5. A condenser as defined in claim 1, wherein each flat tubular element has the following dimensions:
width : 6.0 to 16 mm height : 1.5 to 5.0 mm height of cooling medium flow path : 1.0 mm or more the fin members being the corrugated fins which have the following dimensions:
height : 8.0 to 16 mm fin pitch : 1.6 to 3.2 mm
width : 6.0 to 16 mm height : 1.5 to 5.0 mm height of cooling medium flow path : 1.0 mm or more the fin members being the corrugated fins which have the following dimensions:
height : 8.0 to 16 mm fin pitch : 1.6 to 3.2 mm
6. A condenser as defined in claim 1, wherein each flat tubular element has the following dimensions:
width : 10 to 14 mm height : 2.5 to 4.0 mm height of each cooling medium flow path : 1.5 to 2.0 mm the fin members being corrugated fins which have following dimensions:
height of each fin : 8.0 to 12 mm fin pitch : 2.0 to 3.2 mm
width : 10 to 14 mm height : 2.5 to 4.0 mm height of each cooling medium flow path : 1.5 to 2.0 mm the fin members being corrugated fins which have following dimensions:
height of each fin : 8.0 to 12 mm fin pitch : 2.0 to 3.2 mm
7. A condenser as defined in claim 1, wherein the fin members are corrugated fins provided with louvers on their surface.
8. A condenser as defined in any one of claims 1 to 7, wherein each of the flat tubular elements is made of an aluminum flat extrusion having an elliptical cross-section and having a plurality of bores extending along the length thereof.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000616172A CA1334627C (en) | 1988-09-14 | 1991-09-24 | Condenser |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12082088 | 1988-09-14 | ||
| JP63-120820 | 1988-09-14 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000616172A Division CA1334627C (en) | 1988-09-14 | 1991-09-24 | Condenser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1334796C true CA1334796C (en) | 1995-03-21 |
Family
ID=14795773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000601106A Expired - Lifetime CA1334796C (en) | 1988-09-14 | 1989-05-30 | Condenser |
Country Status (6)
| Country | Link |
|---|---|
| EP (2) | EP0448183A3 (en) |
| KR (2) | KR0184854B1 (en) |
| AT (1) | ATE136639T1 (en) |
| AU (1) | AU618840B2 (en) |
| CA (1) | CA1334796C (en) |
| DE (1) | DE68926202T3 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4020591C2 (en) * | 1990-06-28 | 1995-12-07 | Diesel Kiki Co | Multi-flow condenser |
| FR2665757B1 (en) * | 1990-08-08 | 1997-01-17 | Valeo Thermique Moteur Sa | VERTICAL CIRCULATION REFRIGERANT FLUID CONDENSER AND MANUFACTURING METHOD. |
| JP3044436B2 (en) * | 1994-04-21 | 2000-05-22 | 株式会社ゼクセル | Stacked heat exchanger |
| ATE206515T1 (en) | 1997-05-12 | 2001-10-15 | Norsk Hydro As | HEAT EXCHANGER |
| WO2002081998A1 (en) | 2001-04-04 | 2002-10-17 | Norsk Hydro Asa | Heat exchanger manifold |
| US20030102113A1 (en) * | 2001-11-30 | 2003-06-05 | Stephen Memory | Heat exchanger for providing supercritical cooling of a working fluid in a transcritical cooling cycle |
| KR100913141B1 (en) | 2004-09-15 | 2009-08-19 | 삼성전자주식회사 | An evaporator using micro- channel tubes |
| FR2928448B1 (en) * | 2008-03-04 | 2015-05-01 | Valeo Systemes Thermiques | IMPROVED GAS COOLER |
| DE202011000660U1 (en) * | 2010-03-23 | 2012-01-13 | Akg-Thermotechnik Gmbh & Co. Kg | Heat exchanger, in particular a condensation tumble dryer |
| JP5609916B2 (en) * | 2012-04-27 | 2014-10-22 | ダイキン工業株式会社 | Heat exchanger |
| KR101425042B1 (en) * | 2012-07-26 | 2014-08-01 | 엘지전자 주식회사 | Outdoor heat exchanger |
| WO2014042585A2 (en) | 2012-09-14 | 2014-03-20 | Revent International Ab | Hot air oven |
| EP2722629A1 (en) | 2012-10-16 | 2014-04-23 | Behr GmbH & Co. KG | Capacitor |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1958226A (en) * | 1932-04-06 | 1934-05-08 | Fedders Mfg Co Inc | Condenser for refrigerating apparatus |
| FR2478807A1 (en) * | 1980-03-21 | 1981-09-25 | Deville Ste Indle | Heat exchanger end connection box - has coaxial connections to exterior and also to internal parallel tube groups |
| JPS6334466A (en) | 1986-07-29 | 1988-02-15 | 昭和アルミニウム株式会社 | Condenser |
| DE3765875D1 (en) * | 1986-07-29 | 1990-12-06 | Showa Aluminium Co Ltd | CONDENSER. |
| NL8700641A (en) * | 1987-03-18 | 1988-10-17 | Radson Bv | BOILER ELEMENT. |
| DE3860582D1 (en) * | 1987-03-25 | 1990-10-18 | Johann Schoenhammer | COUNTERFLOW HEAT EXCHANGER. |
| DE3725602A1 (en) * | 1987-08-01 | 1989-02-09 | Sueddeutsche Kuehler Behr | FLAT TUBE FOR A HEAT EXCHANGER |
| DE3730117C1 (en) * | 1987-09-08 | 1988-06-01 | Norsk Hydro As | Method for producing a heat exchanger, in particular a motor vehicle radiator and tube profile for use in such a method |
-
1989
- 1989-05-25 DE DE68926202T patent/DE68926202T3/en not_active Expired - Lifetime
- 1989-05-25 AT AT89305294T patent/ATE136639T1/en not_active IP Right Cessation
- 1989-05-25 EP EP19910201248 patent/EP0448183A3/en not_active Withdrawn
- 1989-05-25 EP EP89305294A patent/EP0359358B2/en not_active Expired - Lifetime
- 1989-05-30 CA CA000601106A patent/CA1334796C/en not_active Expired - Lifetime
- 1989-08-01 KR KR1019890010959D patent/KR0184854B1/en active
- 1989-08-01 KR KR89010959A patent/KR960009342B1/en not_active IP Right Cessation
- 1989-08-30 AU AU40915/89A patent/AU618840B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| KR960009342B1 (en) | 1996-07-18 |
| DE68926202T3 (en) | 2002-05-16 |
| DE68926202T2 (en) | 1996-09-05 |
| EP0448183A3 (en) | 1991-10-16 |
| AU618840B2 (en) | 1992-01-09 |
| EP0359358B1 (en) | 1996-04-10 |
| AU4091589A (en) | 1990-03-22 |
| KR0184854B1 (en) | 1999-05-01 |
| EP0448183A2 (en) | 1991-09-25 |
| ATE136639T1 (en) | 1996-04-15 |
| EP0359358B2 (en) | 2001-10-24 |
| KR900005136A (en) | 1990-04-13 |
| EP0359358A1 (en) | 1990-03-21 |
| DE68926202D1 (en) | 1996-05-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5482112A (en) | Condenser | |
| US5076354A (en) | Multiflow type condenser for car air conditioner | |
| CA2023499C (en) | Duplex heat exchanger | |
| US5458190A (en) | Condenser | |
| US5529116A (en) | Duplex heat exchanger | |
| CA1334796C (en) | Condenser | |
| EP0976999B1 (en) | Heat exchanger | |
| EP0608439B1 (en) | Heat exchanger with improved condensate collection | |
| US5099913A (en) | Tubular plate pass for heat exchanger with high volume gas expansion side | |
| US6070428A (en) | Stack type evaporator | |
| EP1563240B1 (en) | High pressure heat exchanger | |
| WO1998051983A1 (en) | Heat exchanger | |
| KR20060025082A (en) | An evaporator using micro- channel tubes | |
| JPH0581825B2 (en) | ||
| US20040251014A1 (en) | High pressure manifold | |
| EP0415584B1 (en) | Stack type evaporator | |
| JPH03140764A (en) | Heat exchanger | |
| CA1334627C (en) | Condenser | |
| JP2891486B2 (en) | Heat exchanger | |
| JPS63243688A (en) | Condenser | |
| EP0769669A1 (en) | Heat exchanger | |
| JPH03204595A (en) | Condenser | |
| JPS63131993A (en) | Heat exchanger | |
| CA1326481C (en) | Condenser | |
| JPH02146476A (en) | Condenser |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |