7.52         Water at 24°C, 1 bar is drawn from a reservoir 1.25 km above a valley and allowed to flow through a hydraulic turbine-generator into a lake on the valley floor. For operation at steady state, determine the maximum theoretical rate at which electricity is generated, in MW, for a mass flow rate of 110 kg/s. Let T0 5 24°C, p0 5 1 bar and ignore the effects of motion.

7.53         At steady state, hot gaseous products of combustion cool from 2800°F to 260°F as they flow through a pipe. Owing to negligible fluid friction, the flow occurs at nearly constant pressure. Applying the ideal gas model with cp 5 0.25 Btu/ lb ? °R, determine the exergy transfer accompanying heat transfer from the gas, in Btu per lb of gas flowing. Let T0 5 60°F and ignore the effects of motion and gravity.