Lamination Process Enables Microchannel Heat Exchangers

Microchannel array (Oregon State Univ.)

Oregon State University researchers in Corvallis have invented a new way to use lamination to produce microchannel heat exchangers for a number of commercial uses that require efficient heat transfer. Engineering professor Brian Paul and doctoral candidate Prawin Paulraj published their findings in a recent issue of the Journal of Manufacturing Processes (paid subscription required).

Paul says microchannel arrays (pictured right) have enormous potential for more efficient heat transfer and chemical reactions, but their widespread use has been held back by the high production costs of adding the arrays to existing materials. Their new process, says Paul, “could cut production bonding costs by more than 90 percent, compared to existing approaches to microchannel lamination.” Paul adds the new approach has cut material costs by half in some applications.

Microchannels the diameter of a human hair can be patterned into the surface of a metal or plastic, and can be designed to speed up the heat exchange between fluids, or the mixing and separation of fluids during chemical reactions. The accelerated heat and mass transfer leads to smaller heat exchangers and chemical reactors and separators.

Previous advances had demonstrated the use of surface-mounted adhesives to create microchannels on inexpensive aluminum, but bonding aluminum is difficult with conventional techniques. Paul and Pauraj took thin pieces of patterned metal, like aluminum foil, and bonded them one on top of another to increase the number of microchannels in a heat exchanger. This lamination of microchannels makes it possible to increase the amount of fluid the array can process.

The more fluid the array can process, the more efficient the heat-exchange process, and thus the more effective the cooling mechanism for applications such as computers and home electronics that generate heat.  The researchers say that other possible uses include radiators to cool an automobile engine or small, very efficient heat pumps for efficient air conditioning within buildings. Creation of laminated microchannel arrays in materials other than aluminum is possible, including copper, titanium, and stainless steel.

Oregon State’s technology transfer office has applied for a patent on the process and is seeking a private industry partner for commercial development and marketing.

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