An ammonia ice plant operates between a condenser temperature of 35°C and evaporator of -15°C. It produces 10 metric tons of ice per day from water at 30°C to ice at -5°C. Assuming simple saturation cycle, determine the horsepower of the motor if the adiabatic efficiency of the compressor nc = 0.85 and mechanical efficiency nm = 0.95. The specific heat of ice is 2.094 kJ/kg-°C and the latent heat is 335 kJ/kg. From the table for ammonia the following enthalpies are: condenser entrance = 1703 kJ/kg, exit = 366.1 kJ/kg; compressor entrance = 1443.9 kJ/kg, exit = 1703 kJ/kg.

An ammonia refrigeration compressor takes its suction from the evaporator at a temperature of -20oF (-28.9oC) and a quality of 95%. The compressor discharges at a pressure of 100 psi (689.5 kPa), liquid ammonia leaves condenser at 50oF (10oC). Properties of Ammonia:   At 689.6 kPa (Tsat = 13.3oC)      h = 1,568 kJ/kg; s = 5.7676 kJ/kg.K   At 10oC:      hf = 246.531 kJ/kg   At -28.9oC by interpolation      hf = 68.5 kJ/kg; hg = 1424.5 kJ/kg      sf = 0.49366; sg = 6.0452 Determine the quality of refrigerant upon entering to the evaporator.

A two-evaporatoor compression refrigeration system like that in the Figure below uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 30 psia, evaporator 2 at 10 psia, and the condeser at 180 psia. The cooling load for evaporator 1 is 9000 Btu/h and that for evaporator 2 is 24,000 Btu/h. Determine the power required to operate the compressor and the COP of this system. The regrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.

I need help on the following question: The vapour compression cycle (picture provided), utilises the refrigerant R134a flowing at 0.05 kg s-1. Assuming that the compression is adiabatic and reversible. If the actual input power to the compressor is 2 kW, then: 1. You need to determine the theoretical input power to the compressor and the heat transfer (Φ) to theevaporator. Take the enthalpies h1, h2, and h3 to be 238.41, 263.68 and 81.5 kJ kg-1 (use the 'NH3 Refrigeration Table' where you can find online). 2. You need to determine the coefficient of performance based on your answer to the previous question (1). 3. You need to determine the compressors mechanical efficiency.