what is the purpose/justification of replacing the tube bundle? increase duty, corrosion, other(s), . . .
generally, taking an existing tube bundle and replacing it with an identical twisted tube bundle will increase heat transfer capabilities (overall U) of the exchanger, thus allowing for a greater duty.
a wise engr will take into the consideration all the process conditions and perhaps have the exchanger rated (thermally, mechanically, & hydraulically) by the mfg or heat xsfer specialist.
