International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Energy and exergy analysis of deaerator from combined-cycle power plant is presented in this paper. The deaerator is analyzed in three operating regimes and in various ambient conditions. The lowest deaerator energy loss of 525.60 kW and the highest energy efficiency of 78.21 % are obtained for the lowest water temperature at the deaerator outlet – in the same operating regime is obtained the lowest deaerator exergy efficiency. Decrease in the ambient temperature resulted simultaneously with an increase in deaerator exergy destruction and with increase in exergy efficiency. Deaerator exergy efficiency in each operating regime and for each observed ambient temperature significantly varies (from 13.82 % to 45.94 %). From the efficiency aspect, deaerator energy and exergy analysis show diametrically opposed results in two observed operating regimes.

The exergy analysis of deaerator at three different steam power plant loads is performed in this paper. Also, the influence of the ambient temperature change on deaerator exergy efficiency and losses is analyzed. From the exergy viewpoint, deaerator operation shows the best characteristics at middle and high power plant loads. The lowest deaerator exergy destruction of 363.94 kW and the highest exergy efficiency of 93.27 % will be obtained at middle power plant load and at the ambient temperature of 5 °C. The highest deaerator exergy destruction of 1349.99 kW and the lowest exergy efficiency of 81.83 % will be obtained at low power plant load and at the ambient temperature of 45 °C. Deaerator operation is preferable at the lowest possible ambient temperature, regardless of the current power plant load.