To alleviate the severe challenge of energy depletion, it’s extremely urgent to improve the available heat recovery technology. Heat exchangers play a key role in waste heat recovery and have attracted much attention. To recover waste heat, a shell and tube heat exchanger with sinusoidal wavy fins and blocked-core tube inside the tube, and with bare surfaces outside was designed by segmented log-mean temperature difference (LMTD) method. In the shell and tube heat exchanger, liquid water outside the tube was heated by compressed air inside. The effect of air-side inlet pressure on the geometry of heat exchanger was investigated under identical temperature conditions (Ta,i, Ta,o, Tw,i, Tw,o) and water-side inlet pressure. The results show that air-side inlet pressure has little effect on the structure parameters of heat exchanger, but greatly affect the pressure drop of air side.