Experimental characterization of heat transfer in an additively manufactured polymer heat exchanger

In addition to their low cost and weight, polymer heat exchangers offer good anticorrosion and antifouling properties. In this work, a cost effective air-water polymer heat exchanger made of thin polymer sheets using layer-by-layer line welding with a laser through an additive manufacturing process was fabricated and experimentally tested. The flow channels were made of 150 μm-thick high density polyethylene sheets, which were 15.5 cm wide and 29 cm long. The experimental results show that the overall heat transfer coefficient of 35-120 W/m2 K is achievable for an air-water fluid combination for air-side flow rate of 3-24 L/s and water-side flow rate of 12.5 mL/s. In addition, by fabricating a very thin wall heat exchanger (150 μm), the wall thermal resistance, which usually becomes the limiting factor on polymer heat exchangers, was calculated to account for only 3% of the total thermal resistance. A comparison of the air-side heat transfer coefficient of the present polymer heat exchanger with some of the commercially available plain plate fin heat exchanger surfaces suggests that its performance in general is superior to that of common plain plate fin surfaces.