A rigid, well-insulated tank contains a two-phase mixture of ammonia with 0.0025 ft of saturated 3 liquid and 1.5 ft of saturated vapor, initially at . A paddle wheel stirs the mixture until only saturated 3 40 psia vapor at higher pressure remains in the tank. Kinetic and potential energy effects are negligible. For the ammonia, determine the amount of energy transfer by work.

Acommercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -35°c by rejecting waste heat to cooling water that enters the condenser at 18°c at a rate of 0.25 kg/s and leaves at 26°c. the refrigerant enters the condenser at 1.2 mpa and 50°c. if the compressor consumes 3.3 kw of power, determine (a) the mass flow rate of the refrigerant, (b) the refrigeration load, (c) the cop, and (d) the minimum power input to the compressor for the same refrigeration load.