The augmentation in heat transfer by twisted tape inserts has been studied for forced convection condensation of R-22 vapor inside a tube. The inserts are put in the entire length and in 1/4, 1/2, and 3/4 lengths of the test condenser. The pitch ratio, y, for the full-length tape and the segmented tapes is 5.9. The refrigerant flow rate, G, has been taken as 210, 237, 282, 327, and 372 kg/s-m². The enhancement in heat transfer during condensation of R-22 has been attained up to 25% for the full-length twisted tape insert. However, in a certain range of refrigerant flow rates, the 1/2 segmented tape insert has outperformed the full-length tape. It is a general observation that all the twisted tape inserts are more effective at low refrigerant flow rates; however, the full-length twisted tape insert remains effective at the higher refrigerant flow rate as well.

Units: SI