Abstract: In order to study the application of composite phase-change heat exchangers in power plant boilers for waste flue gas recovery, heat exchangers with shuttle and dimple shaped plates were compared via three dimensional numerical simulation using water as the working medium. The simulation results indicate that gas rates in the shuttle-shaped flow channel is significantly higher than that in dimple and flat flow channels, although the profiles are similar. The Nu number of the shuttle-shaped flow channel is higher than that of the dimple flow channel. Meanwhile, the f number keeps unchanged. The performance evaluation criterion (PEC) value of the shuttle-shaped flow channel increases from 1.86~2.11 to 1.98~2.27.