Design and manufacturing of novel hybrid metal-polymer heat exchangers

In the United States, over 50% of the unrecovered energy from industrial processes is in the form of low-grade heat (200◦C). Materials and maintenance costs of common heat exchangers are typically too high to justify their usage. Polymers, though more affordable, are usually unsuitable for heat exchanger applications due to their low thermal conductivity (∼ 0.2 W/mK). Here, we show that metal-polymer hybrids may be attractive from both performance and cost perspectives. The use of polymers further increases the resistance to corrosion by sulfuric and carbonic acids often present in flue gases. This work explores manufacturing different configurations of layered polyimide-copper macroscale hybrids for heat exchanger applications using a modified roll to roll process. We created a manufacturing pathway for producing such layered hybrid tubes that involves directly rolling and bonding tapes made of polymer and copper foil into tubes. A critical problem in the fabrication process is the bonding of metal and polymers. We explore approaches involving adhesives (epoxy, acrylic , and silicone) for metal/polymer interfaces and direct welding (ultrasonic) for metal/metal interfaces that can be integrated into the manufacturing process. We report characterisations of the thermomechanical properties of these joining processes. This work paves way for realizing cost effective manufacturing of heat exchangers for low-grade waste heat recovery