A refrigeration cycle operating between two reservoirs receives energy QC from a cold reservoir at TC = 250 K and rejects energy QH to a hot reservoir TH = 350 K. For each of the following cases determine whether the cycle operates reversibly, irreversibly, or is impossible: (a) QC = 1500 kJ, QH = 2200 kJ, (b) QC = 1500 kJ, Wcycle = 120 kJ, (c) QH = 1600 kJ, Wcycle = 500 kJ, (d) COP = 6.

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]