Efficiency of a closed circuit gas turbine plant

For a cyclic gas turbine plant in which fluid is circulated continuously within the plant (e.g. the plant enclosed within the control surface Y in Fig. 1.2), one criterion of performance 

Chapter 1. A brief review of power generation thermodynamics 

The heat supply to the cyclic gas turbine power plant of Fig. 1.2 comes from the control surface Z. Within this second control surface, a steady-flow heating device is supplied with reactants (fuel and air) and it discharges the products of combustion. We may define a second efficiency for the heating device (or boiler) efficiency. 

0B is the heat transfer from Z to the closed cycle within control surface Y, which occurs during the time interval that A/f, the mass of fuel, is supplied and [CV]q is its calorific value per unit mass of fuel for the ambient temperature (Tq) at which the reactants enter. F = A/f[CV]o is equal to the heat (0o) that would be transferred from Z if the products were to leave the control surface at the entry temperature of the reactants, taken as the temperature of the environment, Tq. Fig. 1.7 illustrates the definition of calorific value. 

The overall efficiency of the entire gas turbine plant, including the cyclic gas turbine power plant (within T) and the heating device (within Z), is given by 

---