Experimental investigation of polymeric heat exchangers with straight and complex 3D-Printed channel geometries: effects of wall resistance on thermal performance

Additive manufacturing (AM) enables the production of complex components with different materials, making it a promising approach for compact heat exchangers. This study investigates the feasibility of AM for fabricating polymer-based heat exchangers using the LCD photopolymerization technique with ABS resin. Three heat exchangers were manufactured: one with straight channels and two with complex 3D geometries (V-shape and Honeycomb). Experimental tests were performed to evaluate thermal performance under different mass flow rates and temperatures, measuring both heat transfer rates and pressure drops. An analytical model, based on the ε-NTU method, was developed to predict the thermal behavior of the straight-channel exchanger. The model demonstrated good agreement with experimental data, with an average difference of about 10%. In contrast, the heat exchangers with complex channels exhibited lower thermal efficiency than the straight-channel exchanger. The reduced performance of the chaotic geometries was attributed to the large wall thickness and low thermal conductivity of the polymer material. Although the chaotic channels increased surface area and induced turbulence, the low thermal conductivity limited the overall heat transfer. This study demonstrates that optimizing channel geometry alone is insufficient to ensure high performance; wall thickness and material selection are critical factors for achieving efficient heat exchangers. The results suggest that AM is a viable technology for fabricating compact polymer-based heat exchangers, with potential for further improvement through enhanced print quality, reduced wall thickness, and the use of materials with higher thermal conductivity.