This preview shows page 1. Sign up to view the full content.
Unformatted text preview: 0.1134 kJ/K 1.5 kg
liquid Vacuum 300 kPa
60°C FIGURE P7–35
7–36 Reconsider Prob. 7–35. Using EES (or other)
software, evaluate and plot the entropy generated
as a function of surroundings temperature, and determine the
values of the surroundings temperatures that are valid for this
problem. Let the surrounding temperature vary from 0 C to
100 C. Discuss your results.
7–37E A piston-cylinder device contains 3 lbm of refrigerant-134a at 120 psia and 120°F. The refrigerant is now cooled
at constant pressure until it exists as a liquid at 90°F. Determine
the entropy change of the refrigerant during this process.
7–38 An insulated piston-cylinder device contains 5 L of saturated liquid water at a constant pressure of l50 kPa. An electric resistance heater inside the cylinder is now turned on, and
2200 kJ of energy is transferred to the steam. Determine the
entropy change of the water during this process, in kJ/K.
Answer: 5.72 kJ/K 7–39 An insulated piston-cylinder device contains 0.05 m3 of
saturated refrigerant-134a vapor at 0.8-MPa pressure. The refrigerant is now allowed to expand i...
View Full Document
This document was uploaded on 11/28/2012.
- Spring '09