using basic thermodynamic concept show how a combined cycle powerplant is superior to either gas turbine power plant or rankine cycle power plant in terms of combined cycle efficiency $.$ Abb combined cycle powerplant generates $250$mw power $,$ Gas turbine produces $180$mw and rankine cycle produces $70$mw $.$ Heat supplied to combustor is $376$mw$.$ GT efficiency is $40\%$ and rankine efficiency is $35\%.$ Hrsg exhaust temparatute is $90$ degree. Energy lost in exhaust is $45$MW