A piston-cylinder device contains 8 kg of refrigerant- 134a at 0.7 MPa and 60C. The refrigerant is

Question:

A piston-cylinder device contains 8 kg of refrigerant- 134a at 0.7 MPa and 60°C. The refrigerant is now cooled at constant pressure until it exists as a liquid at 20°C. If the surroundings are at 100 kPa and 20°C, determine
(a) The exergy of the refrigerant at the initial and the final states and
(b) The exergy destroyed during this process.