US CONSIDER combined cycle plants connected in series, One is the Gas turbine (Brayton cycle) and another is the Steam turbine (Rankine cycle) POWER plant.It is assumed that all the HEAT rejected by the topping cycle is ABSORBED by the bottoming cycle.\({{\rm{η }}_{{\rm{brayton}}}} = 1 - \frac{1}{{{\rm{r}}_{\rm{p}}^{\left( {\frac{{{\rm{\gamma }} - 1}}{{\rm{\gamma }}}} \right)}}}\)Topping cycle → Brayton cycle → Working fluid → HeliumBottoming cycle → Rankine cycle → Working fluid → WaterOverall efficiency,η0 = η1 + η2 - η1η2 η1 = efficiency of the Brayton cycleη2 = efficiency of the Rankine cycle η0 is always more than η1 and η2.