As sketched in Fig. P4.78, a condenser using river water to condense steam with a mass flow rate of 2 x10^5 kg/h from saturated vapor to saturated liquid at a pressure of 0.1 bar is proposed for an industrial plant. Measurements indicate that several hundred meters upstream of the plant, the river has a volumetric flow rate of 2x10^5 m3/h and a temperature of 158C. For operation at steady state and ignoring changes in kinetic and potential energy, determine the river-water temperature rise, in 8C, downstream of the plant traceable to use of such a condenser, and comment

 

AT=? downstream Fig. P4.78 Saturated vapor, P = 0.1 bar m = 2 x 105 kg/h IV Return Industrial plant Condenser min www Saturated liquid, P=0.1 bar 2 Intake (AV) = 2 x 10 m/h T = 15C upstream