I have same problem, now I am designing shell and tube heat exchanger for cooling, shell side will service demin water and tube side will service seawater. Material of shell is Carbon Steel ( A36 ), tube is Titanium, BUT since the budget is very limited, My bos ask me to search another alternative material instead of Titanium ( the expensive one ), recently I heard that there was material tube made from PP (Polypropilene). I think for corrosion resistance from seawater PP is good ( resistant enough)The question are;
1. How about thermal conductivity of PP? is it effective for heat transfer?
2. I read on Book "Process Heat transfer" by Donald Q kern, that in engineering calculation, thermal conductivity of material is ignored because very small impact. Do you agree? Even for Polypropilene?
Thank a lot