problem1) Given and Compute:
a) R-134a at T = 60°C and v = 0.072 m3/kg. Compute P and h.
b) Ammonia at P = 8 bar and v = 0.005 m3/kg. Compute T and u.
c) R-22 at T = -10°C and u = 200 kJ/kg. Compute P and v.
problem2) Given: R-134a is compressed with no heat transfer in piston-cylinder assembly from 30 lbf/in2, 20oF to 160 lbf/in2. Mass of refrigerant is 0.04 lbm. For refrigerant as system, W = -0.56 Btu. Kinetic and potential energy changes might be neglected.
Compute: final temperature (°F).
problem3) Given: Saturated water vapor is contained in the closed rigid tank. The water is cooled to a temperature of 110°C. At this temperature masses of saturated vapor and liquid are each 1000 kg.
Compute: The heat transfer for the process (kJ).
problem4) Given: 0.5 kg of R-22 is contained in the piston-cylinder assembly, initially saturated vapor at 5 bar. Refrigerant undergoes the process for which pressure-specific volume relationship is Pv = C to the final pressure of 20 bar. Kinetic and potential energy effects could be neglected.
a) Work (kJ) and
b) heat transfer (kJ) for the process.
problem5) Given: A gallon of milk at 68°F is placed in a refrigerator. Energy is removed from milk at a constant rate of 0.08 Btu/s a the milk cools. Specific heat, cp,milk = 0.94 Btu/lbmoR and density, rmilk = 64 lbm/ft3.
Compute: How many minutes would it take for the milk to cool to 48°F? How many minutes to cool another 10°F to 38°F?