8-57 Refrigerant-134a at 1 MPa and 100C is throttled to a pressure of 0.8 MPa. Determine the reversible work and exergy destroyed during this throttling process. Assume the surroundings to be at 30C. 8-58 ES Reconsider Prob. 8-57. Using EES (or other) software, investigate the effect of exit pressure on the reversible work and exergy destruction. Vary the throt- tle exit pressure from 1 to 0.1 MPa and plot the reversible work and exergy destroyed as functions of the exit pressure. Discuss the results. 8-59 Air enters a nozzle steadily at 300 kPa and 87C with a velocity of 50 m/s and exits at 95 kPa and 300 m/s. The heat loss from the nozzle to the surrounding medium at 17C is estimated to be 4 kJ/kg. Determine (a) the exit temperature and (b) the exergy destroyed during this process. Answers: (a) 39.5C, (b) 58.4 kJ/kg 8-60 EES Reconsider Prob. 8-59. Using EES (or other) soft- ware, study the effect of varying the nozzle exit velocity from 100 to 300 m/s on both the exit temperature and exergy destroyed, and plot the results.