Air to liquid heat transfer coefficient experimental comparison between silicon carbide and glass shell and tube heat exchangers in a pilot plant scale

Instead of the expected 3.8–5.4% increase in the heat transfer coefficient due to the better thermal conductivity of silicon carbide tubes compared to glass tubes, the observed increase was 18–22% for 150–275kg·h1 airflow and 6kg·s1 propane-1,2-diol coolant in tubes. This additional 15–17% increase is probably due to local flow turbulisation due to the roughness of the sintered carbide of 4–10µm, which unfortunately also causes a 17–24% higher air pressure drop. The hand calculation model used underestimates the heat transfer coefficient by 2% to 10%, which is better than CHEMCAD 8 modeling results.