Performance analysis of two combined cycle power plants with different steam injection system design

The optimum thermal efficiency, for any temperature value during the year, may be obtained for suitable margin of steam injection ratio. The second design presents better overall efficiency then the first one. In winter season (Tam = 15 °C), the overall cycle efficiency is about 54.45% for a range of steam injection ratio within 11.8 and 14%. While in summer season (Tam = 35 °C) and for the same cycle efficiency, the required range of steam injection ratio is between 18.5 and 18.8%.