Arefrigerator with r-134a as the working fluid operates on an ideal vapor-compression refrigeration cycle. the evaporator absorbs 1.5 kw of energy from the chilled space, operating at 120 kpa. the pump pressurizes the refrigerant up to 950 kpa. (a) what is the pump work for this refrigerator? (b) what is the cop of the refrigerator? (c) what is the mass flow rate of the refrigerant through the cycle?

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]