1.5-ibm of water at 350 psia fill a weighted piston-cylinder device whose volume is 1 ft. the water is then heated at constant pressure until the temperature reaches 550°f. determine the resulting change in the water's total entropy. problem 4 refrigerant-134a at 280 kpa and 50°c undergoes an isothermal process in a closed system until its quality is 40 percent. on per unit mass basis, determine how much work and heat transfer are required.

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]