hi guys,... this is my second attempt to ask for help,unfortunately,no one commented on the my previous thread..cry..hop you can help me on this one cos im really a complete newbie....

im planning to design an NH3 tube ice maker system,now,my primary problem is the evaporator design,im thinkin bout the so-called falling film type wherein water is circulated again and again on the vertical tubes,but im stuck on the film coefficient calculations knowing that it continually changes as ice films are formed on the tube walls....anyone can help me figure out any method for this case????or any relation/empirical formula???it really takes me confused considering the fact that it involves a two-phse heat and mass flow,right???please i need ur help and expert knowledge guys.....

also,if ever,im looking for the second option of using brine and tube-shaped cans instead of the falling film system.....is it any good as a replacement?????

hoping for your help.....