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An industrial process is using river water to cool10⁵ kg/h of saturated steam in a heat exchanger at 0.1bar. The cooled steam exits the heat exchanger as a saturatedliquid at the same pressure of 0.1 bar to be used in the process.The river water has a volumetric flow rate of 500 ft³/sand is the coolant in the heat exchanger., having properties closeto pure water (i.e., density – 1000 kg/m³). It existsthe heat exchanger with the same mass flow rate, and is returned tothe river, but at a higher temperature. The river water on a hotsummer day is 20 ⁰C at the heat exchanger inlet, andnear the mixing point of the discharged water from the heatexchanger. Operation is at steady state and kinetic and potentialenergy can be neglected. Since a higher river temperature resultsin lower dissolved oxygen there may be a risk of killing fish oreven “stressing” them. For example, rainbow trout stop growing atsustained river temperatures of 73°F (23° C), and die at about 80⁰F (27 ⁰C). Should the owner of thisindustrial process be concerned for the fishes and localfisherman’s livelihood? Please comment by calculating thetemperature rise of the river at the heat exchanger’s exit thatdischarges into the river.

Hint: properties of thesaturated and compressed water can be found in tables: Table A-3and Table A-5.