Cooling water circuits foul, so the configuration matters as much as the surface area. Removable bundle types where the shell side needs mechanical cleaning, straight tubes where the tube side needs rodding, tube-side velocity kept inside the window that avoids both sedimentation and erosion.
Carbon steel, stainless, cupro-nickel, and duplex construction. Differential expansion, unsupported tube span, and cleaning access checked at design stage rather than discovered in service.
