1. A commercial refrigerator keeps food fresh at -12 ºC. It is estimated that the refrigerator removes 3300 kJ/hr heat from the food, and rejects 4800 kJ/hr heat to the ambient, which is at 30 ºC. Determine the power input to the refrigerator in kW and the COP of the refrigerator.
2. An ice-making plant working on a Carnot cycle heat pump removes 3.5kW heat from the ice, which is maintained at 0 °C and rejects heat to the ambient, which is assumed to be at 25 °C. The work required by the heat pump is supplied entirely by a Carnot heat engine, which operates between a hot reservoir at 220 °C and a cold reservoir at the ambient temperature. Find (a) work output of the Carnot heat engine, (b) Heat absorbed by the Carnot heat engine from the hot reservoir, (c) Total heat rejected into the ambient.