A pistonlcylinder device operating in a cycle with steam as the working fluid executes the following steps:
Saturated-vapor steam at 20.7 bar is heated at constant pressure to 755.15 K (482°C).
The steam then expands, reversibly and adiabatically, to the initial temperature of 487.15 K (214°C). Finally, the steam is compressed in a mechanically reversible, isothermal process to the initial state. What is the thermal efficiency of the cycle?