A vapor power cycle is a thermodynamic cycle that generates power by utilizing the phase change of a working fluid, typically water, from liquid to vapor and back to liquid. The most common vapor power cycle is the Rankine cycle, which consists of four stages: isentropic compression, heat addition in a boiler, isentropic expansion through a turbine, and heat rejection in a condenser. In this cycle, water is pumped to high pressure, heated to produce steam, expanded through a turbine to generate power, and then condensed back to liquid water. Vapor power cycles are widely used in thermal power plants, where they are used to convert the energy stored in fossil fuels or nuclear reactions into electrical energy. By optimizing the design and operation of vapor power cycles, engineers can improve the efficiency and reliability of power generation systems, reduce emissions, and increase the overall performance of power plants. The vapor power cycle plays a vital role in meeting the world's energy demands, and ongoing research and development are focused on improving its efficiency and sustainability.