Patent Application
20130056190
The present invention relates to cooling structures, and in particular, to an integrated monolithic cooling structure.
Traditional cooling structures, for example a radiator or a cooling plate, are heat exchangers used to transfer thermal energy from one medium to another. These heat exchangers typically rely on attaching coolant tubes to a plate to transfer heat to fluid running through the tubes. The cooling tubes are typically attached using thermally conductive epoxies, gaskets, brazed joints, or solder joints.
A heat exchanger structure includes a monolithic extrusion and a plurality of headers. The extrusion includes a first end; a second end; a first, smooth side; and a second side with a plurality of smooth portions alternating with a plurality of raised portions defining a plurality of parallel flow passages extending from the first end to the second end; and a plurality of headers connecting the plurality of flow passages to form a flow path.
A method of forming a heat exchanger structure includes forming an extrusion as a monolithic part with a first end, a second end, a first, smooth side and a second side with a plurality of smooth portions alternating with a plurality of raised portions defining a plurality of elongated flow passages extending from the first end to the second end; and joining the plurality of flow passages with a plurality of headers to form a flow path through the plurality of flow passages.
As shown in
First (smooth) side 12 and second side 14 can be formed by shaping or extruding a profile to define coolant tubes 20 as a monolithic part. First side 12 and second side 14 can be formed of aluminum (including alloys) or another material depending on system requirements. Flow passages 20 are defined by first surface 12 and second surface 14 and extend from first end 22 to second end 23, generally parallel with each other. Headers 24 are welded onto first end 22 and second end 23 of cooling structure to join alternating flow passages 20. Alternatively, headers 24 can be bolted or secured by other means, or can join flow passages 20 in a different configuration, depending on system requirements. In this embodiment, extrusion 10 is curved slightly inward towards second side 14. Extrusion 10 can be joined with other extrusions modularly to form a cooling structure, which can be a complete cylinder radiator or a different shape depending on the application. The extrusion 10, and in particular the first side 12, may be placed in thermal contact with a heat producing source to be cooled.
Cross-sections of flow passages 20 are in the shape of a semi-circle. Cross-sections are extruded to define flow passage shape and size according to the amount of heat exchange required. Additional considerations for forming segment 10 cross-sections can be motor size for the pumping of fluid through flow passages 20 and size and shape of area or article needing heat exchange and space available for flow passages 20.
Cooling structure segment 10 acts as a heat exchanger to transfer heat from first surface 12 to fluid flowing through flow passages 20. Headers 24 connect flow passages 20 so that the plurality of flow passages 20 form a serpentine flow path to circulate a coolant.
By forming cooling structure segment 10 with an integrally extruded piece with semi-circular flow passages 20, cooling structure can efficiently act as a heat exchanger by eliminating barriers to heat exchange of past systems.
Heat is transferred from first surface 33 of panel 32 to fluid flowing through cylindrical tube 34. Solder 36 (or adhesive) in prior art systems acts as an additional barrier of resistance to transferring heat to fluid within flow passage 35. Additionally, flow passage 35 has a much smaller surface area exposed to panel 32 where it is absorbing heat from. This intrinsically causes less heat transfer than a system with a larger surface area for heat-transferring flow passage.
Flow passages 20′ are generally semi-circular and can have a diameter DP of about 0.25 inches (6.35 mm) to about 1.1 inches (27.94 mm). Cross sections generally have two different wall thicknesses. Wall thickness around flow passages 20 TP can be about 0.025 inches (0.635 mm). Wall thickness TF in fin portions 21′ can be about 0.065 inches (1.651 mm). The thinner wall around flow passages 20 allows for enhanced heat transfer in those sections. Wall thickness around flow passages 20 TP and Wall thickness TF in fin portions 21′ are based on the geometry of flow passages 20,′ and can vary depending on system requirements. Pitch P can be about 7.5 inches (190.5 mm).
As seen in
While extrusion 10 is shown to have a curve, alternative embodiments can have a larger curve, smaller curve or no curve at all. Additionally, the size, number and shape of flow passages 20 may vary in different applications. While cross-sections in the embodiments shown in
While the invention has been described with reference to an exemplary embodiment(s), 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 from 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(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
