Application of biomachining on copper for a minichannel heat exchanger

Studies have established a random surface roughness found on the surface of copper after immersion in an Acidithiobacillus ferooxidans-containing culture medium during the biomachining process. In this study, a heat exchanger system was built by employing the biomachining process to manufacture the copper-based minichannel parts for the system. This study investigates the effect of the surface roughness of the minichannel obtained from the biomachining process upon the pressure drop and heat transfer of a fluid flowing through the system. These parameters were also compared to another system possessing minichannel parts with a lower surface roughness made by conventional milling. The result shows that the system containing the biomachined minichannels tends to increase the pressure drop and heat transfer rate of the fluid flow compared to the milled example due to the effect of the roughness average (R_a), which consistently occurred with flow rates (Q) of 32 and 64 mL/min. A novel finding revealed in this study is that the biomachining method can contribute to fluidic channel and heat transfer applications, due to its naturally unique surface roughness.