Design and Additive Manufacturing of a Composite Crossflow Heat Exchanger

Additive manufacturing (AM) with composite materials reveals new possibilities for direct manufacturing of end-use products, breaking the paradigm of 3D printing as only a prototyping or pre-production technique that has been the norm for many AM technologies. A crossflow air-to-water heat exchanger (HX) was designed for manufacturing via fused filament fabrication (FFF). Design iterations improved the manufacturability, considering issues such as geometric fidelity, watertightness, print time, support material, and manufacturing cost. Carbon fiber fillers enhanced the thermal conductivity of the base polyamide resin, allowing for thermal HX performance comparable to conventional aluminum finned tube heat exchangers. The anisotropic thermal conductivity impacts the heat exchanger performance. The design and manufacturing challenges reveal additional routes to continued performance gains as the HX is scaled up to an 8 kilowatt product.