Which of the following statements best describes the Rankine cycle?

The Rankine cycle is best described as a process that involves a phase change, which is a defining characteristic of this thermodynamic cycle. In the Rankine cycle, a working fluid undergoes phase changes between liquid and vapor states as it absorbs heat from a heat source and then releases heat to a heat sink. This cycle typically consists of four main processes: the isentropic expansion of the vapor in a turbine, the heat rejection in a condenser as the vapor condenses to a liquid, the isentropic compression of the liquid by a pump, and the heat addition in a boiler where the liquid turns back into vapor.

Understanding the importance of the phase change in this cycle is crucial, as it allows for the effective conversion of heat energy into mechanical work, which is utilized in many power generation processes. This aspect plays a key role in the efficiency and performance of power plants that operate on the Rankine cycle.

The other options do not accurately represent the essence of the Rankine cycle; it does not operate on a constant volume or constant pressure. While there are constant pressure and constant volume processes in thermodynamics, the Rankine cycle's phases involve substantial changes in volume and pressure. The cycle also does not center around vapor compression, as that description