The condensation of steam from its mixture with air in channels of plate heat exchanger (PHE) is studied experimentally and with calculations based on a mathematical model developed earlier and based on correlations for local process parameters. The experiments are done for five experimental samples modelling the corrugated field of PHE channel with corrugation angle to the main flow direction 30 degrees, 45 degrees, 60 degrees and channel spacing 5 mm, 7.5 mm and 10 mm. The mathematical model validity is confirmed by comparison of calculated temperature program for cooling of air-stream mixture with experimental data for all five samples. The influence of plates corrugations geometry on overall PHE performance in air-stream condensation and local process parameters distribution is discussed. The analysis reveals that to satisfy the required temperature program, PHE with smaller corrugations angle should have plates of bigger length, as well as PHE with bigger channel spacing. Both these parameters can be used as independent variables in the optimisation of plates corrugations geometry for specified process conditions using examined mathematical model.