5 lb/sec of liquid water at 1 atm and 40oF is heated in a vessel by mixing it with 0.6 lb/s of superheated steam at 1 atm and 300oF and produces hot water at 1 atm and 120oF. Calculate the rate of entropy generation. The surrounding temperature is 78oF.

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]