Novel Thin-Sol-Gel Coatings for Biofouling Prevention and Easy Removal

Abstract Heat exchangers are widely used in Navy ships to cool operating fluids and seawater is the preferred cooling medium since it is readily available. However, biofouling will form while ocean water circulates through the heat exchanger tubes or plates, decreasing the heat transfer efficiency and increasing fluid resistance. Further fouling eventually results in more energy consumption and a decrease in heat exchanger service life. To solve the biofouling problem, we developed thin and durable sol-gel coatings that significantly decreased biofouling deposition and facilitated its removal. The developed coatings were applied to titanium substrates and immersed for 64 days at Pearl Harbor, HI. Biofouling formation was followed by taking high-resolution images to quantify the type and extent of biofouling formation. Biofouling adhesion was evaluated by water jet at different nozzle pressures. In addition, the thermal conductivity of the coatings was measured and used as an input parameter for thermal simulations to determine the effect of the coating thickness on the efficiency of a shell and tube heat exchanger.