MET 303 Engineering Thermodynamics 1 Examen 2023

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1. In an air motor cylinder, the compressed air has an internal energy of 450 kJ/kg at the beginning of the expansion and an internal energy of 220 kJ/kg after expansion. If the work done by air during the expansion is 120 kJ/kg, calculate the heat flow to and from the cylinder.

2. A reversible heat engine operates between two reservoirs at 827◦C and 27◦C. Engine drives a Carnot refrigerator maintaining −13◦C and rejecting heat to reservoir at 27◦C. Heat input to the engine is 2000 kJ and the net work available is 300 kJ. How much heat is transferred to refrigerant and total heat rejected to reservoir at 27◦C?