A steam engine and boiler operate on a simple ideal Rankine cycle. Steam enters the engine at 100 kPa and 150 degrees Celsius. The specific volume at this pressure is 0.001043 m3/kg, and the enthalpy is 417.51 kJ/kg. Using enthalpy and entropy, determine the thermal efficiency of this cycle. Note that there is no pump or condenser. The steam simply re-enters the atmosphere, and the boiler is not replenished.