1. Field of the Invention
A heat exchanger assembly for dissipating heat and more specifically, a heat exchanger assembly having fins.
2. Description of the Prior Art
A heat exchanger assembly generally includes a plurality of tubes each extending parallel to and spaced from one another for transferring heat from a refrigerant flowing through the tubes. A plurality of undulating fins zigzag back and forth between adjacent ones of the tubes to define air channels.
Each one of the fins typically define at least one louvered portion which has a plurality of louvers each extending parallel to one another and disposed along a single axis, referred to as the louvered air center. Generally, if included the louvers of a second louvered portion are also disposed along the same single axis. The louvers are angled relative to the fin surface such that the louvers divert some of the air flowing through each of the air channels through the fin and into adjacent air channels.
Louvered air center performance is critical to the heat transfer rate of compact heat exchangers, such as radiator, heaters, condensers, and evaporators. A typical louvered air center includes a plurality of louvered portions on each fin, e.g., a leading margin, a turn-around margin, and a trailing margin. The actual airflow path in the air center can be theoretically divided into two different flow paths, louver flow and channel flow. Channel flow is defined as the flow along the air channels. Louver flow is defined as the flow between the louvers into adjacent air channels. The greater the percentage of air flowing between the louvers as louver flow, the greater the heat transfer and airflow efficiency.
For a given distance between two groups of louvers, i.e., the width of each air channel formed by the zigzagging fin, smaller louver widths result in a thinner thermal boundary layer which increases heat transfer for the assembly. On the other hand, the smaller louver widths also result in a larger gap between two adjacent groups of louvers, i.e., a larger air channel width, which results in a higher percentage of channel flow and therefore lower heat transfer performance. Accordingly, in the current heat exchanger fin designs, there is an optimum louver width for a given air channel width wherein performance cannot be further improved.
Although the prior heat exchanger assemblies are sufficient for their intended purposes, there is a continuing need for more efficient and improved assemblies.
The invention includes a louvered portion having a plurality of first louvers each extending in a height direction along a first louver centerline as well as a plurality of second louvers each extending in the height direction along a second louver centerline. The first louver centerlines are parallel to one another and disposed side by side along a first axis extending in a width direction transverse to the height direction and the second louver centerlines are parallel to one another and disposed side by side along a second axis extending in the transverse width direction. The first louvers are disposed at a first angle and the second louvers are disposed at a second angle relative to the transverse width direction. The second axis extends parallel to said first axis and spaced from said first axis in a length direction transverse to the height direction and the width direction.
The invention reduces the thermal boundary layer of each louver which improves performance while simultaneously reducing the amount of channel flow which also improves performance.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a heat exchanger assembly for dissipating heat is generally shown. As shown in
A plurality of fins 22 each are zigzagged back and forth in the height direction AH between adjacent ones of the tubes 20 for receiving heat from the tubes 20. The fins 22 are disposed along the length direction AL between the ends of the tubes 20 to define an air channel 24. The air channels 24 extend between the sides of the tubes 20 in the width direction AW.
Each one of the fins 22 define at least one louvered portion 26 to divert some of the air flowing through each of the air channels 24, through the fin 22 and into an adjacent one of the air channels 24.
As shown in
The louvered portion 26 also has a plurality of second louvers 30 each extending in the height direction AH along a second louver centerline CL2. Similarly, the second louver centerlines CL2 are parallel to one another and disposed side by side along a second axis A2 extending in the transverse width direction AW. The second louvers 30 are also parallel to one another and are all disposed at a second angle θ2 relative to the transverse width direction AW.
The second axis A2 extends parallel to the first axis A1 and is spaced from the first axis A1 in the length direction AL, as best shown in
As best shown in
The first distance a, the second distance b, and the first angle θ1 are interrelated according to a first relationship defined as tan−1(a/b)≠1.
In one embodiment shown in
The first angle θ1 may be equal to the second angle θ2, as shown in
The first louver centerlines CL1 of the first louvers 28 are each spaced equidistant from one another. Similarly, the second louvers 30 are each spaced equidistant from one another.
In one embodiment shown in
Each one of the third louver centerlines CL3 is spaced from a corresponding one of the second louver centerlines CL2 in the length direction AL by the first distance a. Each one of the third louver centerlines CL3 is also offset from the corresponding one of the second louver centerlines CL2 in the width direction AW by the second distance b.
Each of the third louver centerlines CL3 are offset from corresponding ones of the second louver centerlines CL2 in the width direction AW by the first distance a and are spaced from corresponding ones of the second louver centerlines CL2 in the length direction AL by the second distance b. The angles (θ1, θ2, θ3) may all be equal to one another, as shown in
In operation, air flowing through the air channels 24 is diverted through the louvered portions 26 of the zigzagging fin 22 and into adjacent air channels 24. Because the invention requires multiple rows of louvers 28, 30, 32 for each louvered portion 26, the width of each louver may be reduced, reducing the thermal boundary layer and increasing heat transfer, without reducing the gap in the length direction AL between two parallel louvered portions 26, i.e., without reducing the width of the air channels 24. Accordingly, the invention surpasses the heat transfer of prior assemblies by decreasing louver width below that of the optimum width of the prior assemblies while maintaining the same air channel 24 width.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing form the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Number | Date | Country | |
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61020048 | Jan 2008 | US |