Power Cycle ApplicationsAt steady state, a 750-MW power

QUESTION:

At steady state, a 750-MW power plant receives energy by heat transfer from the combustion of fuel at an average temperature of \(317^{\circ} \mathrm{C}\). As shown in Fig. P5.40, the plant discharges energy by heat transfer to a river whose mass flow rate is \(1.65 \times 10^{5}\) kg/s. Upstream of the power plant the river is at \(17^{\circ} \mathrm{C}\). Determine the increase in the temperature of the river, \(\Delta T\), traceable to such heat transfer, in \({ }^{\circ} \mathrm{C}\), if the thermal efficiency of the power plant is (a) the Carnot efficiency of a power cycle operating between hot and cold reservoirs at \(317^{\circ} \mathrm{C}\) and \(17^{\circ} \mathrm{C}\), respectively, (b) two-thirds of the Carnot efficiency found in part (a). Comment.