A closed rigid tank contains Refrigerant 134a initially at T

A closed rigid tank contains Refrigerant 134a, initially at T_1 = 100degreeC. The tank is cooled until it becomes a saturated vapor at = 20degreeC. Assume changes in kinetic and potential energy are negligible. Sketch process on T - v and p - v diagrams Determine the initial and final pressures, p_1, P_2 [bar] Determine heat transfer [kJ/kg] during the process (indicate magnitude and direction)

Solution

initial pressure at 100 C is 39.72 bar

final pressure is 5.71 bar

initial enthalpy = 309.037 kj/kg

final enthalpy = 127.437 kj/kg

heat transfer = 309.037 -127.437= 181.6 kj/kg