Exergy analysis of combined cycles using latest generation gas turbines

The potential performance of optimized gas-steam combined cycles built arou nd latest-generation gas turbine engines is analyzed, by means of energy/ex ergy balances. The options here considered are the reheat gas turbine and t he H-series with closed-loop steam blade cooling. Simulations of performanc e were run using a well-tested Modular Code developed at the Department of Energy Engineering of Florence and subsequently improved to include the cal culation of exergy destruction of all types (heat transfer, friction, mixin g, and chemical irreversibilities). The blade cooling process is analyzed i n derail as it is recognized to be of capital importance for performance op timization. The distributions of the relative exergy destruction for the tw o solutions-both capable of achieving energy/exergy efficiencies in the ran ge of 60 percent-are compared and the potential for improvement is discusse d.